Land area increase in Ukrainian part of the Danube delta

The quantitative indicators of land growth in the Ukrainian part of the Danube delta are considered. Comparison of Landsat satellite images in three key areas of the delta showed that for the period 1975-2020 the area of wetlands at the mouth of the Сhilia channel increased by 1448 hectares due to the accumulation of sediments between the Starostambul and Limba branches and their overgrowth with vegetation. In the area of the Bystroe channel, the area of new lands increased by 1037 hectares due to the artificial deepening of this channel for the Ukrainian ships passage into the Danube River and the deposition of sediments along the coast. A slightly smaller increase in land cover (797 ha) was found in the northern part of the coast of the Ukrainian part of the delta, where saline and carbonate soils are formed. In the future, active land growth is expected in the Musura bay between the mouths of the Starostambul and Sulina branches, ie at the contact of Ukraine and Romania. Some changes in these parameters are expected after a powerful flood in 2021, which will become known after the establishment of a relative equilibrium between the processes of accumulation and erosion after this extreme event.

Initial Succession After Wildfire in Dry Boreal Forests of Northwestern North America

Wildfires in the boreal forest of North America are generally stand renewing, with the initial phase of vegetation recovery often governing the vegetation trajectory for decades. Here, we investigate post-fire vegetation changes in dry boreal forests of the Northwest Territories, Canada, during the first five years following the unusually severe 2014 wildfire season. We sampled post-fire tree regeneration and the overall plant community at one, three, and five years post-fire across different fire severities and stand types within fires that burned in 2014. Post-fire trajectories of tree recruitment, cover by plant functional types, and plant diversity varied widely among sampled stands, as well as among years post-fire. Tree seedling density reaches relative equilibrium by three years post-fire, whereas trends in understory plant cover and understory species assemblages suggest an ongoing change that will extend beyond five years of observation. In almost half of sampled stands, the composition of recruited trees differs from that of the pre-fire stand, suggesting a change in tree-species dominance. An analysis of regional climate reveals a significant, albeit spatially variable, warming and drying trend that will further accelerate forest-stand transformation through both climate drivers of plant community composition and indirectly through increasing fire activity. While the 2014 wildfires enhanced the structural and compositional heterogeneity of the region, they also triggered vegetation changes that are likely to be persistent. As such, this study exemplifies the speed and variability that characterizes post-fire stand development in a strongly moisture-limited part of North America.

Natural and human control of the coastal development. Baltic sea, Lithuania

Sea coast - a geomorphic system that maintains its stability through the exchange of sand between its individual elements. As environmental conditions change, the shore system changes by adapting to maintain its stability. Natural processes such as sea level fluctuation and extreme storms cause continuous shoreline change. Feedback effects create natural elements inhibiting external factors altering shore stability. There is a relative equilibrium between natural factors and the shore and in the absence of sudden changes the shore system retains its quasi-stability over a long period of time. This is reflected in the development of the Baltic Sea coast at Lithuania in the 20th century. During this period, of naturally developing coastline did not experience drastic changes. Both the position of the shoreline and the change in the volume of sand on shore did not undergo catastrophic changes. Everything changes radically when a human intervenes in natural processes by starting to develop economic activities on the shore. Especially significant changes occur during the construction or reconstruction of hydro-technical structures. In the case of Lithuania, the hydro-technical structures that caused the biggest changes were the jetties of Klaipeda and Šventoji ports and the pier of Palanga. Since the shore sand transfer resultant at the Lithuanian nearshore is directed from south to north, the resulting barrier cats this drift, disrupting the free circulation of sand along the shore and forcing sand to accumulate on the southern side of the jetty. Meanwhile, on the north side of the jetty, when the sand supply is lost, the coast begins to retreat. These changes are exacerbated by the deepening of the Klaipeda port cana

Application of software tools for symbolic description and modeling of mechanical systems

The paper presents two software tools (graphical editor and software package). The editor is designed for the formation of a symbolic description of a mechanical system using the Lagrange formalism. A system of the absolutely rigid bodies connected by joints is considered as a mechanical system. The editor is a user interface by which one sets the structure of the interconnection of bodies (system configuration) as well as the geometric and kinematic characteristics for each body of the system. The created structure and the entered data are automatically presented in the form of a text file, which is used as an input file for the software package for modeling mechanical systems in a symbolic form with a computer. The use of these software tools is shown in detail in the example of the analysis of the dynamics of a satellite with a gravitational stabilizer in a circular orbit. For this system, the kinetic energy and force function of an approximate Newtonian gravitational field were obtained, nonlinear and linearized equations of motion were constructed, and the question of the stability of the relative equilibrium position was considered.

Use of the information technologies at the international level of public communications

The importance of the use of the information technologies at the present stage of human development in all spheres of activity has been noted. Their use can significantly increase the efficiency of tasks related to the processing of the large amounts of information, its storage, transmission, retrieval, etc. Implementation and use of the information technologies in the activities of the Internal Affairs will allow to increase productivity. Development and implementation of the modern information technologies are taking place in many areas, and comprehension of their application will help to avoid unnecessary costs and more effectively implement them in the activities of the Internal Affairs. It has been noted that influence of factors both at the macrolevel and at the global level derives the system from its relative equilibrium state and encourages to decision-making relative to bringing the system to a new level with a relatively stable state. Such a factor is the global pandemic, and the tools to overcome it are the latest information systems and technologies. Emphasis has been placed on the development of new areas and technologies in global communication between different areas of activity, and the use of digital platforms has been proved to be promising, which provides a number of opportunities. The evolution of law enforcement agencies has been provided and macrolevel tendencies which determine their development have been stood out. Innovations in the practical activities of law enforcement agencies have been shown, which translate the processes to a higher technological and organizational level through the use of the information technologies. Global trends in the development of new information technologies have been investigated, and in terms of the benefit of their use in law enforcement agencies, their sequence has been provided. Priority of their use can be represented as follows: big data analytics, artificial intelligence, cloud solutions, Internet of Things and so on. It has been emphasized that the urgent needs of the present time act as factors in the development of the new information technologies, and, in the same time, the information sphere acquires systemically formative significance for society.