Among the Arctic seas, the largest volume of river runoff (~45% of the total river-water inflow into the Arctic Ocean) enters the Siberian Kara Sea. The viral communities of the Kara Sea are important for the functioning of the marine ecosystem. Studies of virus–prokaryote interactions on the Kara Sea shelf have been conducted only in spring and autumn. Here, we investigated the abundance of free viruses, viruses attached to prokaryotes, and pico-sized detrital particles; the morphology (shape and size) of the viruses, viral infection and virus-mediated mortality of prokaryotes in early summer, i.e., during a seasonal ice melting period and maximum inflow of river-water volumes with high concentrations of dissolved and suspended organic carbon. Seawater samples for microbial analyses were collected across the Kara Sea shelf zone on board the Norilskiy Nickel as a research platform from June 29 to July 15, 2018. Abundances of prokaryotes (range (0.6–25.3) × 105 cells mL−1) and free viruses (range (10–117) × 105 viruses mL−1) were correlated (r = 0.63, p = 0.005) with an average virus: prokaryote ratio of 23.9 ± 5.3. The abundance of free viruses and viral-mediated mortality of prokaryotes were significantly higher in early summer than in early spring and autumn. Free viruses with a capsid diameter of 16–304 nm were recorded in the examined water samples. Waters in the Kara Sea shelf contained high concentrations of suspended organic particles 0.25–4.0 µm in size (range (0.6–25.3) × 105 particles mL−1). The proportions of free viruses, viruses attached to prokaryotes, and viruses attached to pico-sized detrital particles were 89.8 ± 6.0%, 2.2 ± 0.6% and 8.0 ± 1.3%, respectively, of the total virioplankton abundance (on average (61.5 ± 6.2) × 105 viruses mL−1). Viruses smaller than 60 nm clearly dominated at all studied sites. The majority of free viruses were not tailed. We estimated that an average of 1.4% (range 0.4–3.5%) of the prokaryote community was visibly infected by viruses, suggesting that a significant proportion of prokaryotic secondary production, 11.4% on average (range 4.0–34.0%), was lost due to viral lysis. There was a negative correlation between the abundance of pico-sized detrital particles and the frequency of visibly infected prokaryotic cells: r = −0.67, p = 0.0008.

The use of program code as a data source is increasingly expanding among data scientists. The purpose of the usage varies from the semantic classification of code to the automatic generation of programs. However, the machine learning model application is somewhat limited without annotating the code snippets. To address the lack of annotated datasets, we present the Code4ML corpus. It contains code snippets, task summaries, competitions, and dataset descriptions publicly available from Kaggle—the leading platform for hosting data science competitions. The corpus consists of ~2.5 million snippets of ML code collected from ~100 thousand Jupyter notebooks. A representative fraction of the snippets is annotated by human assessors through a user-friendly interface specially designed for that purpose. Code4ML dataset can help address a number of software engineering or data science challenges through a data-driven approach. For example, it can be helpful for semantic code classification, code auto-completion, and code generation for an ML task specified in natural language.

The article considers the experience of eco-tourism development in European countries. The basic principles of ecotourism are high-lighted. The types of protected natural terri-tories are identified and the degree of severi-ty of the prohibition of the applicability of forms of use of natural territories is deter-mined. The analysis of the current state of ecotourism development is also carried out on the example of the Russian subjects of the Kaliningrad and Leningrad regions. The study of scientific works allowed us to de-termine the role of ecological tourism in the development of protected natural areas. The development of ecological tourism in special-ly protected natural areas contributes to the formation of people's understanding of the importance of natural areas for the conser-vation of biological diversity.

The article discusses the basic principles of the implementation of the transition from a linear economy to a circular economy model. The article summarizes the existing problems that require solutions to create new jobs, increase economic growth, and create a balance between the economy, environment and population. The authors present examples of building a circular economy model in foreign countries. The importance of the tasks of implementing and promoting the circular economy was revealed, thanks to the involvement of all participants in the society in this process and the motivation for companies and investors. Effective tools for moving society towards a resource-efficient closed-cycle economy, increasing energy efficiency, energy conservation and reducing the energy intensity of the gross domestic product, due to the entry into a competitive level of renewable energy sources are investigated. The introduction of digital technologies and artificial intelligence in automated accounting of resource consumption, as well as the improvement of accounting rules will create opportunities for the end user to manage resource consumption taking into account the principles of a circular economy. The authors' study emphasizes that circular economy products and services should minimize resource use and promote reuse, recovery and recycling of materials in the future, leveraging existing product policy instruments, further support for the repair sector, improved design for reuse, and high-quality packaging recycling. The authors in the article propose to legislate the subsidizing of enterprises participating in the circular chain and subsidizing innovative developments in the field of the circular economy in the Russian Federation.