Exact Solutions of the Equations of Relativistic Hydrodynamics Representing Potential Flows

We use a connection between relativistic hydrodynamics and scalar field theory to generate exact analytic solutions describing non-stationary inhomogeneous flows of the perfect fluid with one-parametric equation of state (EOS) $p = p(\epsilon)$. For linear EOS $p = \kappa \epsilon$ we obtain self-similar solutions in the case of plane, cylindrical and spherical symmetries. In the case of extremely stiff EOS ($\kappa=1$) we obtain ''monopole + dipole'' and ''monopole + quadrupole'' axially symmetric solutions. We also found some nonlinear EOSs that admit analytic solutions.Comment: This is a contribution to the Proc. of the Seventh International Conference ''Symmetry in Nonlinear Mathematical Physics'' (June 24-30, 2007, Kyiv, Ukraine), published in SIGMA (Symmetry, Integrability and Geometry: Methods and Applications) at http://www.emis.de/journals/SIGMA

Bioenergetic and ethological features of the first-calf heifers of different genotypes

The aim of this work was to study bioenergetic and ethological indicators in crossbred first-calf heifers compared to purebred first-calf heifers. The research was conducted on the first-calf heifers of Ukrainian Black-Pied dairy breed and first-generation crossbreeds obtained as a result of crossing with Brown Swiss breed, as well as, on the first-calf heifers of Ukrainian Red-Pied dairy breed and first-generation crossbreeds obtained as a result of crossing Ukrainian Red-Pied dairy with Montbéliarde breed. The purebred Black-and Red-Pied first-calf heifers prevailed over crossbreed first-calf heifers on the indicator of milk yield for 305 days of lactation by 106.45 and 218.36 kg, respectively. Accordingly, the indicators of average daily milk yield were also higher by 0.35 and 0.72 kg and the indicators of average daily milk yield adjusted by 4 % fat content per 0.15 and 0.16 kg. At the same time, the indicator of average fat content in milk prevailed in crossbreeds of Black-Pied and Brown Swiss breed by 0.08 % compared to purebred Black-Pied breeds, and in Red-Pied crossbreeds with Montbéliarde breed by 0.16 % compared to purebred Red-Pied breeds. The purebred Black-Pied first-calf heifers had an advantage by 2.04 MJ compared to crossbreeds, while the Red-Pied first-calf heifers had a slight advantage by 0.06 MJ compared to crossbreed first-calf heifers on the indicator of daily cost of exchange energy (EE). The purebred Black-and Red-Pied first-calf heifers had higher cost of exchange energy allocated with milk compared to crossbreed first-calf heifers by 0.42 and 0.82 MJ. They also had higher cost of exchange energy rates for heat products by 0.79 and 0.25 MJ. According to the energy index indicator, purebred Black - and Red-Pied first-calf heifers prevailed over crossbreeds first-calf heifers by 0.16 and 0.07 %, respectively. The same trend was observed in relation to the productive index indicator. The purebred Black-and Red-Pied first-calf heifers had a slight advantage by 0.001 and 0.002 kg adjusted by 4 % of milk fat content per 1 MJ. According to the indicators of daily behavioral reactions, no special differences between a purebred and crossbreed were found

Composition and cheese suitability of milk from local Ukrainian cows and their crossbreedings with Montbeliarde breed

Received: July 19th, 2022 ; Accepted: September 8th, 2022 ; Published: September 12th, 2022 ; Correspondence: [email protected] aim of this work was to compare the qualitative composition of milk and its suitability for cheese processing at cows of local Ukrainian Red-Spotted breed (URS) and their crossbreeds with Montbeliarde (MO) breed. The research was conducted at commercial farm in the Vinnytsia region, Ukraine (48° 57′01″ n.l., 28° 47′09″ e.l). At farm, two groups of purebred and crossbred first lactation cows-analogues with a population of 20 heads in each were formed. The use of crossbreeding cows URS × Montbéliarde breed had a positive effect on the milk composition and cheese suitability. It was established that local purebred cows exceeded purebred counterparts in daily milk yield by 2.47 kg. When the content of fat, protein and lactose in milk was higher in crossbreed group by 0.19, 0.19 and 0.12%, respectively. In addition, crossbreed cows surpassed purebred counterparts for the energy value of 1 kg of milk and theoretically possible output of rennet cheese by 0.142 MJ and 0.61 kg. The duration of the coagulation phase of milk obtained from crossbred cows was shorter than that of purebred analogues by 1.54 minutes

Indicators of the behavior of highly productive cows under the conditions of using feed stations

The purpose of this work was to study the influence of feed stations on behavioral indicators of high-yielding cows. The research was conducted at two farms of TDV “Terezine” (Kyiv region) with different options for feeding fodder: from a feed table and a feed table + at feed stations. On each farm, a group of unpregnant high-yielding cows of the Ukrainian black-spotted dairy breed (II lactation and older) with a daily productivity of 30 kg and above during the calving period (2–3 months of lactation) was formed. Using feed stations for concentrated feeds affected the daily behavior of high-yielding cows. With this option of feeding, lower values of the duration of walking and standing were observed (by 16.3 and 9.6 min), as well as a slightly longer duration of lying down rest – by 17.4 min. The total feeding duration was longer due to the consumption of concentrated feeds at feeding stations, which was 25.6 minutes. At both farms, the peak of daily foraging activity occurred at 08:00 and 18:00. On average, during the day, cows approached the feed table and ate feed 8.7 times (maximum 12, minimum 6). At the farm with concentrated fodder feeding at feed stations, the average hourly duration of fodder consumption from the feed table was slightly lower (by 1–8 min) than at the farm where cows were fed only with fodder mixtures. At the farm, with the use of feed stations, the values of the indices of comfort, use of stalls, and feeding were 3.14, 1.62, and 0.03 % higher compared to the option where cows were fed only with feed mixtures. This trend is explained by a slightly higher duration of rest and general feed consumption and, accordingly, a lower duration of walking and standing of animals. Somewhat lower values were for the index of standing, discomfort, and drunkenness, which were higher for feeding feed from the feed table – by 1.79, 0.04, and 0.008%, respectivel

Amino acid composition of milk from Finnish Ayrshire cows and their crossbreeds with the Norwegian Red breed

Received: July 28th, 2023 ; Accepted: October 18th, 2023 ; Published: October 30th, 2023 ; Correspondence: [email protected] purpose of this work was to study the effect of crossing of Finnish Ayrshire cows with Norwegian Red breed under the conditions of the temperate climate of Ukraine on indicators of the qualitative composition of milk, the content of essential amino acids (EAA) and their biological value. The research was conducted at a commercial farm in the Poltava region (50°02′39″ n.l., 33°51′09″ e.l.) using Finnish Ayrshire cows and their crosses with the Norwegian Red breed. According to the indicators of fat, protein and lactose content in the group of crossbred firstborns, purebred counterparts prevailed by: 0.22; 0.09 and 0.07%, respectively, and the energy value of 1 kg of milk by 0.053 Mcal kg-1 . For milk protein of Finnish Ayrshires, the first limiting EAA (lower than the recommended content in the reference protein) was methionine + cystine (affects the rate of clot formation during cheese making), the content of which was 96.3%. In the protein of crossbred cows EAA in which amino acid score (AAS) was less than 100%, were not detected. Phenylalanine + tyrosine - 143.7% and leucine - 122.1%, which are aromatic amino acids and affect the taste properties of milk, were the most excessive. The protein of crossbreds was characterized by a slightly higher value of the total utilitarian coefficient, compared to purebred counterparts (by 12.77%). Also, the aminogram of the crossbred group was closer to ‘ideal’

Detailed description of accelerating, simple solutions of relativistic perfect fluid hydrodynamics

In this paper we describe in full details a new family of recently found exact solutions of relativistic, perfect fluid dynamics. With an ansatz, which generalizes the well-known Hwa-Bjorken solution, we obtain a wide class of new exact, explicit and simple solutions, which have a remarkable advantage as compared to presently known exact and explicit solutions: they do not lack acceleration. They can be utilized for the description of the evolution of the matter created in high energy heavy ion collisions. Because these solutions are accelerating, they provide a more realistic picture than the well-known Hwa-Bjorken solution, and give more insight into the dynamics of the matter. We exploit this by giving an advanced simple estimation of the initial energy density of the produced matter in high energy collisions, which takes acceleration effects (i.e. the work done by the pressure and the modified change of the volume elements) into account. We also give an advanced estimation of the life-time of the reaction. Our new solutions can also be used to test numerical hydrodynamical codes reliably. In the end, we also give an exact, 1+1 dimensional, relativistic hydrodynamical solution, where the initial pressure and velocity profile is arbitrary, and we show that this general solution is stable for perturbations.Comment: 34 pages, 8 figures, detailed write-up of http://arxiv.org/abs/nucl-th/0605070

Organizational, regulatory and legal aspects оf european integration of higher medical education in Ukraine: a critical review

The aim: The main purpose of this research is to conduct the theoretical and applied study of the legal profile enforcement for state attestation of medical graduates, the relevant legislative system, and its effectiveness; to identify the issues of special legislative requirements, as well as the search for ways to resolve it. Materials and methods: Basic methods: analysis, synthesis and comparison. Object of research: system of state certification of graduates of medical sciences. Investigation of this topic in the paper is carried out in the following logical sequence: firstly, the basic principles of the state integrated qualification exam were determined and analyzed; then the legal enforcement for integrated state qualification exam of master’s degree in discipline “22 Health Care” was considered. Also, a critical review of Ukrainian normative base for holding the state attestation of medical graduates was conducted. Conclusions: In view of foregoing, we can make a conclusion that in the modern globalization world, competition of national educational services should be ensured by a range of different activities: legal, organizational, financial, etc. The legal direction, domestic rules should correspond to similar, uniform rules and practices of the most effective state (regional, international) systems