On the hierarchy of partially invariant submodels of differential equations

It is noticed, that partially invariant solution (PIS) of differential equations in many cases can be represented as an invariant reduction of some PIS of the higher rank. This introduce a hierarchic structure in the set of all PISs of a given system of differential equations. By using this structure one can significantly decrease an amount of calculations required in enumeration of all PISs for a given system of partially differential equations. An equivalence of the two-step and the direct ways of construction of PISs is proved. In this framework the complete classification of regular partially invariant solutions of ideal MHD equations is given

Spray nozzle designs for agricultural aviation applications

Techniques of generating monodisperse sprays and information concerning chemical liquids used in agricultural aviation are surveyed. The periodic dispersion of liquid jet, the spinning disk method, and ultrasonic atomization are the techniques discussed. Conceptually designed spray nozzles for generating monodisperse sprays are assessed. These are based on the classification of the drops using centrifugal force, on using two opposing liquid laden air jets, and on operating a spinning disk at an overloaded flow. Performance requirements for the designs are described and estimates of the operational characteristics are presented

Spectrophotometric experiment on the Verera-11 and Venera-12 descent vehicles: Some results of the analysis of the spectrum of the daytime sky of Venus

The spectra of the daytime sky of Venus were recorded on the Venera-11 and Venera-12 descent vehicles at various altitudes above the planet's surface, within the interval of 4500 to 12,000 Angstroms. The angular distribution of the brightness of the scattered radiation was recorded and the ratio of water and carbon dioxide were studied, with respect to the cloud cover boundaries

The reflective environment as a means of formation professional reflection of the future specialist

The article discusses some of the characteristics of reflexive educational environment as a means of formation of professional reflection of the future specialist. Shows the importance of reflection for professional activitiesРассматриваются некоторые характеристики рефлексивной образовательной среды как средства формирования профессиональной рефлексии будущего специалиста. Показано значение рефлексии для профессиональной деятельност

Analysis of the influence of chronic heart failure type on changes in the microelement composition of myocardial tissue in patients of senile age

Aim: conduct a comparative analysis of the content and distribution of macroelements (Ca2+, K+, Mg2+, and Na+) in myocardial tissue according to autopsy data in elder patients with CHF, depending on the LV E

Pharmacotherapy for the prevention of the progression of chronic heart failure in elderly patients with coronary heart disease

Aim: chronic heart failure (CHF), which occurs as a result of common cardiovascular diseases in the elderly, combined with age-related changes in both structural and functional features of the heart. Myocardial remodeling is an essential substrate that determines the occurrence and progression of CHF in elderly patient

Trematode fauna of fish inhabiting reservoirs of the European part of Russia

The purpose of the research is an ecological and faunal analysis of trematodes in fish inhabiting reservoirs of the European part of Russia.Materials and methods. Helminthological studies were conducted in 23 reservoirs of the European part of Russia from 2011 to 2021. The fish aged two to seven years were analyzed by methods generally accepted in ichthyoparasitology.Results and discussion. Twelve fish species from families Cyprinidae, Percidae, Esocidae and Odontobutidae were found to be infected with 29 trematode species from 14 genera which were represented by 68.9% of metacercariae. Most trematodes had a wide specificity: Tylodelphys clavata was found in 9 fish species; Diplostomum spathaceum and Paracoenogonimus ovatus in 7 species and Apophallus muehlingi in 6 species. The expanded host range for T. podicipina was observed. A. muehlingi, which is an alien species for the Volga-Caspian fisheries basin was identified in most reservoirs. Trematodes by their prevalence in reservoirs are divided into background (5 species), common (6), rare (8) and very rare (10) trematodes. Trematode fauna of fish in reservoirs included 6 to 16 species. The highest species diversity was detected in the Belgorod (16 species), Yakhroma (13 species), Uglich and Chelnav (12 species), Pestovsk and Pyalovsk (11 species) reservoirs. Fifteen trematode species were found in the perch; 12, in the bream and roach; 9, in the pike perch; 8, in the pike and rudd; 6, in the ruff and white bream; 4, in the Volga pikeperch and crucian carp; 3, in the tench; and 1, in the Amur sleeper. The formed foci of trematode infections were observed, namely, postodiplostomosis and ichthyocotylurosis infection. Three trematode species, Pseudoamphistomum truncatum, A. muehlingi and Rossicotrema donicum, were detected that pose a real and potential danger to human health and warm-blooded animals

Sub-nanosecond Pulse Generation from a Two-section Laser-thyristor: Theoretical Analysis

We have developed a theoretical model of a two-section laser-thyristor. It is shown that using a 4 µm weakly doped p-base can increase blocking voltage up to 50 V, which makes it possible to generate 2 ns 10 A current pulses. It is demonstrated that the proposed device utilizes passive Q switching to generate high-power short optical pulses that account for up to 80% of output power. By picking the optimal passive section length, we have achieved optical pulses of ∼30 ps full width at half maximum (FWHM) and ∼100 W peak power.     Keywords: pulsed laser, semiconductor N-p-N-i-P heterostructure, laser-thyristor, dynamic model of pulsed lase