Decentralized finance (DeFi) protocols use blockchain-based tools to mimic banking, investment and trading solutions and provide a viable framework that creates incentives and conditions for the development of an alternative financial services market. In this respect, they can be seen as alternative financial vehicles that mitigate portfolio risk, which is particularly important at a time of increasing uncertainty in financial markets. In particular, some DeFi protocols offer an automated, low-risk way to generate returns through a “delta-neutral” trading strategy that reduces volatility. The main financial operations of DeFi protocols are implemented using appropriate algorithms, but unlike traditional finance, where issues of value and valuation are commonplace, DeFis lack a similar value-based analysis. The aim of this study is to evaluate relevant DeFi performance metrics related to the valuations of these protocols through a thorough analysis based on various scientific methods and to show what influences the valuations of these protocols. More specifically, the study identifies how DeFi protocol valuations depend on the total value locked and other performance variables, such as protocol revenue, total revenue, gross merchandise volume and inflation factor, and assesses these relationships. The study analyzes the valuations of 30 selected protocols representing three different classes of DeFi (i.e., decentralized exchanges, lending protocols and asset management) in relation to their respective performance measures. The analysis presented in the article is quantitative in nature and relies on Granger causality tests as well as the results of a fixed effects panel regression model. The results show that the valuations of DeFi protocols depend to some extent on the performance measures of these protocols under study, although the magnitude of the relationships and their directions differ for the different variables. The Granger causality test could not confirm that future DeFi protocol valuations can be effectively predicted by the TVLs of these protocols, while other directions of causality (one-way and two-way) were confirmed, e.g., a two-way causal relationship between DeFi protocol valuations and gross merchandise volume, which turned out to be the only variable that Granger-causes future DeFi protocol valuations.

In this article, we present our own construction process model consisting of 16 stages and eight phases, which is particularly applicable to large investment projects. In the context of each project phase, we examine how the appropriate way of scheduling construction processes affects the problem of the risk of prolonging individual phases and the whole project, as well as of not meeting deadlines (which is one of the main problems faced by management practitioners in the construction industry). There are many methods for assessing risk in this context, but they tend to be overly complex and rarely used by construction practitioners. On the other hand, the risks associated with potential schedule delays can be considered holistically. One tool that can serve this purpose is the combined Monte Carlo simulation and Time-at-Risk (TaR) approach, which originates from the world of finance. We show how the implementation of the process model (individual phases) and the whole project can be considered in the context of the covariance matrix between all its phases and how changes in the arrangement of these phases can affect the risk of time extension of the whole project. Our study is based on simulation data for a large development project (Fort Bema/Parkowo-Leśne housing estate complex) in Bemowo, a district of Warsaw, carried out between 1999 and 2012. The entire investment project involved the construction of almost 120,000 m² of floor space.

In 2022, Poland and Germany experienced a prolonged and extensive mass fish kill in the Odra River. During the period from the end of July to the beginning of September 2022, a high level of incidental disease and mortality was observed in various fish species (dozens of different species were found dead). The fish mortality affected five Polish provinces (Silesia, Opole, Lower Silesia, Lubuskie, and Western Pomerania) and involved reservoir systems covering most of the river (the Odra River is 854 km long, of which 742 km are in Poland). Fatal cases were investigated using toxicological, anatomopathological, and histopathological tests. Water samples were collected to determine nutrient status in the water column, phytoplankton biomass, and community composition. High nutrient concentrations indicated high phytoplankton productivity, with favorable conditions for golden algal blooms. The harmful toxins (prymnesins secreted by Prymnesium parvum habitats) had not been found in Poland before, but it was only a matter of time, especially in the Odra River, whose waters are permanently saline and still used for navigation. The observed fish mortality resulted in a 50% decrease in the fish population in the river and affected mainly cold-blooded species. Histopathological examinations of fish showed acute damage to the most perfused organs (gills, spleen, kidneys). The disruption to hematopoietic processes and damage to the gills were due to the action of hemolytic toxins (prymnesins). An evaluation of the collected hydrological, meteorological, biological, and physico-chemical data on the observed spatio-temporal course of the catastrophe, as well as the detection of three compounds from the group of B-type prymnesins in the analyzed material (the presence of prymnesins was confirmed using an analysis of the fragmentation spectrum and the accurate tandem mass spectrometry (MS/MS) measurement, in combination with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS), allowed the formulation and subsequent testing of the hypothesis for a direct link between the observed fish mortality and the presence of prymnesins in the Odra River. This article systematizes what is known about the causes of the fish kill in the Odra River in 2022, based on official government reports (one Polish and one German) and the EU technical report by the Joint Research Centre. A review and critical analysis of government findings (Polish and German) on this disaster were conducted in the context of what is known to date about similar cases of mass fish kills.

Urban flooding is an increasingly common phenomenon around the world. The reasons are usually attributed to the insufficient capacity of the combined sewer system and its inability to adapt to the changing dynamics of rainfall. This is also the case in Warsaw (the capital of Poland), where the sewage system was designed in the 1960s. The aim of the article is to highlight possible hydrological solutions that would significantly improve Warsaw’s situation in terms of rainfall runoff. The article looks at some solutions that were previously mentioned in the literature and presents an assessment of the possible changes in land use/land cover on the hydrological processes and improvements in the general hydrological situation of Warsaw. In addition, the article points out the need to update the programme and spatial approach to the discharge of water from specific watersheds in Warsaw, as well as to establish a single manager for stormwater drainage in the city of Warsaw. An important issue is the restoration of natural retention basins in the city and the construction of artificial basins in places with frequent local flooding. The article emphasises the importance of building individual detention basins (as well as low-impact developments) for newly planned investments. Other important aspects are as follows: the construction of suitable underground or open channels, the need to disconnect Ursynów’s stormwater runoff from the catchment area of the Służewiecki Stream and to channel it along the southern bypass for Warsaw (S-2) to the dry lakes and ponds in Wilanów. Finally, the article discusses the application of Sustainable Drainage Systems (SuDS) and Real-Time Control (RTC) in urban drainage systems as a possible solution to improve wastewater management in urban areas.

The deteriorating housing situation of young adults in many countries has become a subject of global interest. Researchers point to a number of factors that influence young adults’ decisions to own or rent a home. This paper examines the relationship between young adults’ inclination to own their own home and a range of different socio-economic factors. The study is of a quantitative-qualitative nature and was based on the results of a computer-assisted web interview (CAWI) questionnaire. The survey was conducted among young Poles aged 18–45 (n = 983). To analyse the results of the questionnaires, a logistic regression was used in which 24 different dichotomous and categorical variables were considered. Taking into account a number of individual characteristics (e.g., gender, education, hometown population size, etc.), the results show, for example, that single individuals and those with a higher level of tolerance for mortgage interest rates are more likely to own a home than to rent. This result highlights the desirability of easier access to mortgage credit. At the other end of the spectrum are those living with parents and those with dependents. The results imply that they are less interested in buying a home. Interestingly, declarations of a lack of funds for an own contribution when buying a new house/dwelling, or reluctance to expose oneself to financial difficulties throughout one’s life, do not discourage young adults from striving for their own dwelling, which further demonstrates the need to create appropriate mechanisms/instruments to facilitate the purchase of a dwelling for young adults.

The future of opencast mining and energy production based on conventional resources is one of the most important issues being discussed in international forums. The whole discussion is becoming increasingly heated and takes on a special significance with the drastic increase in energy commodity prices that has occurred with the outbreak of war in Ukraine. Especially in a country like Poland, these issues are accompanied by heated discussions between miners, the government and citizens. It should be emphasised that Polish lignite mining currently produces about 35% of the cheapest electricity in Poland and also creates many jobs. The aim of this study is to assess the possibility of continuing opencast mining and its impact on rural development—both from an environmental and socio-economic point of view. The study was conducted for two municipalities in Poland where opencast lignite mining plays an important role, namely Kleszczów and Kleczew. As a result, it was found that in the case of the studied municipalities, the presence of opencast mining has contributed to their development, and the application of modern environmental protection technologies and recultivation have reduced the difficulties associated with mining. On the other hand, the decision to start mining should be the result of a comparison between the potential environmental and social benefits and damages. In some cases, mining is beneficial for community development and leads to new opportunities for agriculture and tourism after reclamation. The study is a combination of different methods, i.e., case studies, GIS remote sensing analysis (based on Landsat data) and econometric analysis for selected socio-economic data.