Geodemographic Dynamics of Crimean Population: Main Trends and Factors of Post-Soviet Period

The article examines the geodemographic dynamics of the Crimea in the post-Soviet period: changes in the population of the peninsula, its centers and territories; changeable ratio of natural and migration components, and shifts in the settlement system. In the dynamics of the processes under analysis, four stages are distinguished: three of them relate to the Ukrainian period of the Crimea’s development, and the last one it is the Russian stage which begins in 2014. Until the mid-1990s (the first stage), the population of the peninsula continues to grow, despite the natural decline and increased outflow to Russia. The main reason for this is the large-scale re-emigration of Crimean Tatars to the peninsula, most of whom settle in the interior of the Crimea. The next stage (late 1990s – the middle of the 2000s) is associated with a significant depopulation of the region, primarily due to a high natural population decline. The third stage (the second half of the 2000s – the beginning of the 2010s), at which the depopulation is replaced by a minimal increase in the population of the peninsula, is associated with an improvement of the indicators of its natural reproduction and a certain increase in the migration influx. The features of the Russian development stage are set by two multi-component processes. Migration activity is determined by the consequences of the transition of the Crimea to Russia. Meanwhile in the natural reproduction, a central role is played by a small generation of the 1990s entering into the reproductive age, with such consequences as a rapid decline in the birth rate and an increase in natural loss. The result of these processes is a certain stabilization of the population of the Crimea. The situation in which the natural decline is offset by the migration influx is likely to continue in the nearest future and in the medium term period (until 2030–2035). The main trend in the spatial distribution of the demographic potential of the Crimea in the last 15–20 years is a gradual increase in the proportion of the population settled on the coast and in the coastal zone 15–20 km wide.

Prediction and Controlling of Auditory Perception in Augmented Environments. A Loudness-Based Dynamic Mixing Technique

At the core of augmented reality audio (ARA) technology lies the ARA mix, a process responsible for the assignment of a virtual environment to a real one. Legacy ARA mix models have focused on the natural reproduction of the real environment, whereas the virtual environment is simply mixed through fixed gain methods. This study presents a novel approach of a dynamic ARA mix that facilitates a smooth adaptation of the virtual environment to the real one, as well as dynamic control of the virtual audio engine, by taking into account the inherent characteristics of both ARA technology and binaural auditory perception. A prototype feature extraction technique of auditory perception characteristics through a real-time binaural loudness prediction method was used to upgrade the legacy ARA mix model into a dynamic model, which was evaluated through benchmarks and subjective tests and showed encouraging results in terms of functionality and acceptance.

Riverbed Substrate Requirements for Natural Reproduction of Gymnocypris przewalskii

Gymnocypris przewalskii (i.e., Qinghai Lake naked carp) is a migratory fish species that lives in highland brackish water. It is important to understand the abiotic environment required by this fish to reproduce naturally so that its habitat can be protected and the wild population can be conserved. Here, artificial simulation and spawning ground substrate transformation experiments were conducted to examine the riverbed substrate requirements for G. przewalskii to naturally reproduce. Using various techniques (in vitro markers, videography, and Ethovision XT behavior tracking), this study systematically investigated the riverbed substrate preferences of G. przewalskii as well as the characteristics and effectiveness of natural reproduction induced by pebble riverbed substrate. The findings can be summarized as follows: (1) the habitat preferences of G. przewalskii differed significantly between various riverbed substrate, with pebble substrate being preferred during natural reproduction, and sand substrate being preferred pre- and post-spawning, and (2) the natural reproduction of G. przewalskii was heavily reliant on pebble riverbed substrate. Specifically, pebble substrate significantly improved spawn quantity and fertilization rate. These findings provide scientific evidence for the improvement and restoration of G. przewalskii spawning grounds, and insights regarding the artificial bionic reproduction of G. przewalskii.

Foundation and Prospects of Wild Population Reconstruction of Acipenser dabryanus

Acipenser dabryanus is an endemic fish inhabiting the upper reaches of the Yangtze River in China. It is classified as a first-class nationally protected animal in China and is listed in the International Union for Conservation of Nature (IUCN) Red List of Critically Endangered Species (CR). Recently, there has been a decrease in natural reproduction of A. dabryanus, and the wild population is almost extinct. This paper summarizes the changes observed in the natural population of A.dabryanus and the factors leading to its endangerment. Based on the process of artificial propagation and achievement of relevant protection goals, this paper presents the concept and technical framework for reconstruction of the wild population of A. dabryanus. In addition, by comprehensively reviewing the research findings and existing problems in the resource protection and monitoring of A. dabryanus in recent years, we assessed the possibility of wild population reconstruction and resource restoration for A. dabryanus. Reconstruction and restoration measures for the wild population of A. dabryanus are proposed, with the aim of providing a scientific basis for the reconstruction of the natural population and the improvement and restoration of critical habitat of this species. Furthermore, it is hoped that this paper will serve as a reference for the protection and restoration of other endangered fishes.

Dezvoltarea unui complex mobil pentru reproducerea ecologo- industrial a speciilor pelagofile de pești în condiții de fluvii și lacuri

The populations of most fish species in the Republic of Moldova reproduce naturally, however, as a result of the increasing anthropogenic impact on aquatic ecosystems, the conditions for their natural reproduction have deteriorated significantly. In this context, one of the research objectives for 2020 was the development of efficient technological principles for conservation and rational use of local fish stock. It was revealed the ensuring of the development of the most vulnerable stages in the ontogenesis of fish in controlled environmental conditions is one of the basic principles of productivity management of Danube mackerel populations. In order to put into practice the principles of managing the productivity of breeding stocks, a mobile installation has been developed for the reproduction of pelagophilous fish species.

Natural Reproduction of the Population of Russia during the Coronavirus Pandemic: Risks and Consequences (The Case of the Republic of Tatarstan)

Introduction. The study is of relevance due to the decline in the population of the Russian Federation since 2018 and the aggravation of the demographic situation since 2020, during the COVID-19 pandemic. Based on the results of analyses of demographic indicators of natural population growth in the Russian Federation, in the Volga Federal District, and in the Republic of Tatarstan, the article identifies the factors affecting such indicators during the spread of coronavirus infection. Materials and Methods. The study analyzed operational data from the Federal State Statistics Service and the Unified Interdepartmental Information and Statistical System on the demographic indicators (birth rate, mortality, marriage rate, and divorce rate). The comparative, cross-sectional, correlation, and regression methods of analysis were employed, which made it possible to reveal significant factors affecting the demographic situation and identify the general trend of demographic processes during the COVID-19 pandemic. Results. On the basis of the official statistics, an analysis of the demographic situation in terms of natural reproduction of the population of Russia, exemplified by the case of the Republic of Tatarstan has been carried out; the main factors in natural population decline during the COVID-19 pandemic have been identified; the need for the introduction of new measures aimed at improving health and reducing the mortality rate and overcoming the demographic crisis in marriage and family relations has been substantiated. Discussion and Conclusion. Conclusions have been drawn about the possibility of increasing the negative impact of the coronavirus pandemic on the future demographic situation, which is a threat to the national security of Russia. The significance of the research materials consists in a comprehensive analysis of the demographic situation caused by the natural population change. The results of the study can be used by the authorities in the development and adjustment of regional and federal demographic and social policies.

DETERMINATION OF THE EFFECTIVENESS OF WORK ON ARTIFICIAL REPRODUCTION OF COREGONUS PELED IN THE OB-IRTYSH BASIN

The method of determining the effectiveness of artificial reproduction works is considered on the example of the Ob population of peled. The method is based on recording the moment when the population decline stops, and the subsequent increase in catches. Based on the average fishing return rate of 0.258% of the 1.5 g young, the catch from one million young is about 0.8 tons. It is established that the catch can increase to 2.6 tons per one million juveniles after the entry into the fishery of new offspring from the replenishment of the spawning herd. Taking into account the mass onset of sexual maturity of the peled at the 4th year of life, the greatest effect of artificial reproduction is observed at the 8th year. The equations for determining the period and level of restoration of the bioresource are given. It is noted that for the restoration of long-cycle fish species, the volume of young fish introduction should be at least 20 % of the receiving capacity. The rate of recovery of the bioresource depends on the following indicators: the volume of the introduction of juveniles, the intensity of fishing, the age of sexual maturity and the availability of conditions for natural reproduction.

Abortion occurs during double fertilisation and ovule development in Paeonia ludlowii

Paeonia ludlowii, a rare and endangered species, is indigenous to Tibet, China and propagated only by seed. Its natural reproduction is constrained by low fecundity. Excess seed abortion is a key factor restricting its natural reproduction, cultivation, introduction, and protection. In this study, we examined the characteristics of aborted ovules, developmental differences after flowering of normal and aborted ovules, and their ratios at different positions in P. ludlowii ovary. During pollination, fertilisation, and seed development, ovule abortion was frequent, with a random abortion position. There were four types of abortion, namely, abnormal pistil, sterile ovules, abnormal embryo sac, embryo and endosperm abortions. Of these, embryo and endosperm abortions could be divided into early abortion, middle abortion, and late abortion. The early aborted ovules stopped growing on day 12, the endoblast and endosperm in the embryo sac aborted gradually. Furthermore, the shape of the embryo sac cavity changed. The volume of aborted ovules was significantly different from that of fertile ovules. At ripening, the external morphology of different types of aborted seeds was significantly different.

RECOMMENDATIONS OF MAXIMUM PERMISSIBLE VOLUMES OF RELEASE OF AQUATIC BIOLOGICAL RESOURCES: REGULATORY REGULATION AND PRACTICAL IMPLEMENTATION

The addition of natural reproduction of hydrobionts by the fish farming to provide a fishery resources and preserve the biological diversity of water ecosystems. Fish farming based on scientific recommendations in Russia according to federal legislation. The need to develop scientific recommendations has been related to the fact conditions of each water body determine the number of fish juveniles that can be provided with conditions for their growth. Currently, the term "maximum permissible volumes of release" (PDOV) used in regulatory documents governing the development of recommendations for fish farming. At the same time, the definition of this term is not given in the legislation, which implies its interpretation. The lack of explicit wording of the term makes it possible to use a variety of approaches and methods in the preparation of recommendations. Аs expected, the use of different methods gives different results. There is debate about the eligibility of applying different approaches when discussing the results, since each expert has a different view on the problem of determining the maximum permissible number for release. This situation indicates the need to approve unified methodological approaches to assessing the maximum permissible number of fish juveniles to release. It is necessary to supplement governing document with provisions in which, based on the availability and quality of available information on the reproduction conditions and the feed base of juvenile fish, existing methodological approaches to determining the maximum permissible number for release, various levels of information support can be distinguished to substantiate the maximum permissible number of fish juveniles.