THE PECULIARITIES OF THE PRENATAL MORPHOGENESIS OF THE EPIDIDYMIS

Epididymis serves a critical function in the process of sperm cells maturation, since it provides with a unique liquid microbiomedium that allows maturation and survival of the spermatozoa. Therefore, the aim of our study is to clarify the patterns of the morphogenesis of the epididymis during the perinatal period of human ontogenesis. 27 series of the serial histological sections of the human embryos and prefetuses (4.0-80.0 mm of parietal-coccygeal length (PСL)) and 56 specimens of human fetuses (81.0-375.0 mm PCL) have been studied, using the methods of microscopy, macroscopy, graphic and plastic reconstruction and morphometry. It has been found that the anlage of the epididymal tubules occurs in the prefetuses 14,0-16,0 mm of PCL, and the formation of the epididymal segments (caput, corpus and cauda), as well as establishment of the correlation between the tubules of the testicle and epididymis is observed in prefetuses 18,0-65,0 mm of PCL. At the early fetal period the asymmetry of the shape and size of the right and left epididymises is observed; it is preserved during the entire fetal period and is accompanied by the process of their accelerated and slowed development. At the end of the fetal period of the ontogenesis the structure and shape of the epididymal tubular system is close to the definite state

Ways to Improve the Communicative Skills of Pedagogical Specialties Students in the Higher Educational Institutions

Solving communication problems in the digital environment is becoming increasingly difficult for both teachers and students. The formation of communicative skills of future teachers in the learning process is also important from the standpoint of increasing relevance in the development of emotional intelligence of the personality. The purpose of the academic paper was to develop and test a model of formation of communicative skills of future teachers in the process of studying at higher educational institutions (HEI). The research methodology is based on a quantitative assessment of the formation success of communication skills in the process of teaching the course “Psychology” for 120 students of the Faculty of Philology in Ukraine. Qualitative analysis of the effectiveness of the developed formation model of future teachers’ communicative skills involved observing the teachers’ and students’ behavior of control and experimental groups of the course. The results demonstrate the effectiveness of the proposed formation model of future teachers’ communicative skills in the process of studying at HEI

Simulation as a method for asymptotic system behavior identification (e.g. water frog hemiclonal population systems)

Studying any system requires development of ways to describe the variety of its conditions. Such development includes three steps. The first one is to identify groups of similar systems (associative typology). The second one is to identify groups of objects which are similar in characteristics important for their description (analytic typology). The third one is to arrange systems into groups based on their predicted common future (dynamic typology). We propose a method to build such a dynamic topology for a system. The first step is to build a simulation model of studied systems. The model must be undetermined and simulate stochastic processes. The model generates distribution of the studied systems output parameters with the same initial parameters. We prove the correctness of the model by aligning the parameters sets generated by the model with the set of the original systems conditions evaluated empirically. In case of a close match between the two, we can presume that the model is adequately describing the dynamics of the studied systems. On the next stage, we should determine the probability distribution of the systems transformation outcome. Such outcomes should be defined based on the simulation of the transformation of the systems during the time sufficient to determine its fate. If the systems demonstrate asymptotic behavior, its phase space can be divided into pools corresponding to its different future state prediction. A dynamic typology is determined by which of these pools each system falls into. We implemented the pipeline described above to study water frog hemiclonal population systems. Water frogs (Pelophylax esculentus complex) is an animal group displaying interspecific hybridization and non-mendelian inheritance

Gamete production patterns and mating systems in water frogs of the hybridogenetic Pelophylax esculentus complex in northeastern Ukraine

Hybridization and polyploidy play an important role in animal speciation. European water frogs of the Pelophylax esculentus complex demonstrate unusual genetic phenomena associated with hybridization, clonality and polyploidy which presumably indicate an initial stage of reticulate speciation. The Seversky Donets River drainage in north-eastern Ukraine is inhabited by both sexes of the diploid and triploid hybrid P. esculentus and only one parental species Pelophylax ridibundus. Based on the presence of various types of hybrids, all populations studied can be divided into three geographical groups: I) P. ridibundus—P. esculentus without triploids; II) P. ridibundus—P. esculentus without diploid hybrids; and III) P. ridibundus—P. esculentus with a mixture of diploids and triploids. A study of gametogenesis revealed that diploid P. esculentus in populations of the first type usually produced haploid gametes of P. ridibundus and a mixture of haploid gametes that carried one or another parental genome (hybrid amphispermy). In populations of the second type, hybrids are derived from crosses of P. ridibundus males with triploid hybrid females producing haploid eggs with a genome of P. lessonae. Therefore, we suggest that clonal genome duplication in these eggs might be the result of suppression of second polar body formation or extra precleavage endoreduplication. In populations of the third type, some diploid females can produce diploid gametes. Fertilization of these eggs with haploid sperm can result in triploid hybrids. Other hybrids here produce haploid gametes with one or another parental genome or their mixture giving rise to new diploid hybrids

Устойчивость сперматогенеза и проявления отбора на клеточном и индивидуальном уровнях у незрелых представителей Pelophylax esculentus complex

Pelophylax esculentus is an interspecific hybrid which reproduces hemiclonally by crossing with the parental species (P. ridibundus or P. lessonae). The structure of hemiclonal population systems is of great interest. The majority of investigations into populations of water frogs deal with samples of mature animals, while subadults are less studied. We collected a random sample of 73 small water frogs from three localities in the Siverskyi Donets River floodplain. All frogs were measured, injected with colchicines and killed after anesthesia. We determined the species specifity, sex, age and ploidy of every individual. In addition, we measured testis length and studied the germ cells of all males by means of karyological analysis. We calculated the portion of triploids in the largest subsample from the vicinity of the Biological Station of V.N. Karazin Kharkiv National University and carried out a meta-analysis of previous publications dealing with composition of green frog samples from this locality. The proportion of triploids in our sample appeared to be approximately the same as 12 years ago. However, this proportion in our sample differed significantly from that obtained in recent samples of green frogs belonging to other age groups (adults and metamorphs) from the same locality. The share of triploids of P. esculentus is the lowest in the sample of metamorphs. This proportion increases in froglets because of early death of representatives of parental species which originated from hybrid-hybrid crossing. Then the number of triploids among adult P. esculentus individuals declines again probably because of their lower viability compared to diploids. We have revealed that subadult diploids have erythrocytes smaller than 28 microns, while triploids’ erythrocytes exceed 27 microns. Therefore, in borderline cases true ploidy could be determined only by the karyological technique. The average ratio between testis length and body length appeared to be larger in the parental species than in both diploid and triploid hybrids. Karyological analysis has revealed that P. esculentus had significantly lower portions of spermatocytes I with normal karyotype (13 bivalents) in the testis in comparison with P. ridibundus, but this value increases in adult hybrids. We suggest that increasing of spermatogenesis stability in adult frogs as opposed to subadults might be the consequence of both selection of germ cell lines in the testis and more frequent survival of individuals with stable gametogenesis. Исследована случайная выборка неполовозрелых зеленых лягушек из Северско-Донецкого центра разнообразия Pelophylax esculentus complex. У каждой особи определяли пол, возраст (методом скелетохронологии), плоидность и принадлежность к P. esculentus или P. ridibundus, а также измеряли длину тела и длину семенников у самцов. По мазкам крови определяли среднюю длину эритроцитов. Из семенников изготавливали кариологические препараты, по которым описывали кариотипы клеток во время митотических и мейотических делений. Проведен метаанализ результатов данной и предшествовавших работ, в которых определяли состав выборок зеленых лягушек пойме р. Северский Донец в окрестностях Биологической станции Харьковского национального университета имени В.Н. Каразина. Доля триплоидных P. esculentus ниже всего у метаморфов, повышается (вследствие гибели представителей родительского вида, появляющихся от скрещивания гибридов) у незрелых особей и снижается (из-за большей смертности триплоидов) у половозрелых особей. Диплоидные лягушки имеют длину эритроцитов менее 28 мкм, триплоидные – более 27 мкм; в диапазоне 27–28 мкм по длине эритроцитов установить плоидность невозможно. Незрелые P. esculentus имеют тенденцию к задержке развития гонад и значимо большее количество аномальных кариотипов в митозе и мейозе, чем P. ridibundus. Повышение устойчивости сперматогенеза у половозрелых лягушек по сравнению с незрелыми может быть следствием как отбора клеточных линий внутри семенников, так и преимущественного выживания особей с относительно более устойчивым гаметогенезом.Исследована случайная выборка неполовозрелых зеленых лягушек из Северско-Донецкого центра разнообразия Pelophylax esculentus complex. У каждой особи определяли пол, возраст (методом скелетохронологии), плоидность и принадлежность к P. esculentus или P. ridibundus, а также измеряли длину тела и длину семенников у самцов. По мазкам крови определяли среднюю длину эритроцитов. Из семенников изготавливали кариологические препараты, по которым описывали кариотипы клеток во время митотических и мейотических делений. Проведен метаанализ результатов данной и предшествовавших работ, в которых определяли состав выборок зеленых лягушек пойме р. Северский Донец в окрестностях Биологической станции Харьковского национального университета имени В.Н. Каразина. Доля триплоидных P. esculentus ниже всего у метаморфов, повышается (вследствие гибели представителей родительского вида, появляющихся от скрещивания гибридов) у незрелых особей и снижается (из-за большей смертности триплоидов) у половозрелых особей. Диплоидные лягушки имеют длину эритроцитов менее 28 мкм, триплоидные – более 27 мкм; в диапазоне 27–28 мкм по длине эритроцитов установить плоидность невозможно. Незрелые P. esculentus имеют тенденцию к задержке развития гонад и значимо большее количество аномальных кариотипов в митозе и мейозе, чем P. ridibundus. Повышение устойчивости сперматогенеза у половозрелых лягушек по сравнению с незрелыми может быть следствием как отбора клеточных линий внутри семенников, так и преимущественного выживания особей с относительно более устойчивым гаметогенезом

Проблеми організації навчально-виховного процесу у вищих навчальних закладах з урахуванням технологій здоров’язбереження

Грицай, Ю. О. Проблема організації навчально-виховного процесу у вищих навчальних закладах з урахуванням технологій здоров’язбереження / Ю. О. Грицай, С. В. Бірюк // Педагогічні науки : наук. вісн. МНУ. – Миколаїв : МНУ ім. В. О. Сухомлинського, 2016. – № 2 (53). – С. 56–58.У статті розглядаються питання організації навчального-виховного процесу з фізичного виховання у вищих навчальних заклада з урахуванням технологій здоров’язбереження, проблеми зміцнення здоров'я студентської молоді та виховання стійкої потреби в систематичних заняттях фізичною культурою.The article discusses the introduction of organization of the educational process of higher educational institutions with the health-saving technologies, the problems of strengthening of health of student's youth education and sustainable need in systematic physical exercises.В статье рассматриваются вопросы организации учебного-воспитательного процесса по физическому воспитанию в высших учебных заведения с учетом технологий здоровьесбережения, проблемы укрепления здоровья студенческой молодежи и воспитание устойчивой потребности в систематических занятиях физической культурой

Sustainable coexistence of the parental species and hemiclonal interspecific hybrids is provided by the variety of ontogenetic strategies

Factors determining the sustainability of Hemiclonal Population Systems in which the interspecies hybrids Pelophylax esculentus complex coexist with members of parental species were studied using a combination of empirical data and computer simulation modeling. The empirical data demonstrates the existence of different intrapopulation strategies by partitioning a sample of individuals into two groups on the basis of their body size at a given age and comparing selected groups in terms of factors such as growth rate, life span, females’ fecundity and the age at which breeding commences. Then by using simulation modeling, we study the probable importance of intrapopulation ontogenetic strategies for the stability of Pelophylax esculentus complex HPS

On Unbounded Composition Operators in L2L^2-Spaces

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied