The article is concerned with the finds of four bronze coins of Bithynia unearthed in the territory of the present-day state of Belarus: a coin of Hadrian from Rehispolle (Minsk Voblasts), which belongs to the so-called coins of the Koinon of Bithynia, and coins with the images of Julia Domna (Kopcevichy, Vitebsk Voblasts), Macrinus (Yuzafovа, Vitebsk Voblasts), and Gordian III (Pruzhany, Brest Voblasts), all issued by the mint at Nicaea. The authors argue that the coins may have reached Belarus from the Danubian provinces as well as directly from Nicaea (present-day İznik in Turkey), i.e., from those locations or territories where their participation in monetary circulation was the greatest. It is most likely that those coins may have been seized by the Barbarians during their incursions into the Roman provinces in the course of the Gothic Wars (3rd century CE).

This article presents the results of research on the importance of access to critical raw materials for the development of wind energy in Poland. The authors have built a set of factors that can potentially influence this development. Twenty-four explanatory variables were taken into account, which were assigned to five categories. The amount of demand for mineral resources related to the development of wind technology was determined using a computer programwritten by the authors. The importance of individual factors was verified using the ARMAX model. As a result of this, it was possible to identify the explanatory variables that significantly affect the volume of wind energy production in Poland. The group of mineral resources includes critical metals that are necessary for the production of wind turbines. These are rare earth elements, copper, nickel, boron and manganese. The ARMAX model enables the examination of the relationship between the explained variable and the explanatory variables. Optimization of the model parameters was performed by limiting the mean square error. During the validation of the model, the VIF (variance inflation factor), Dickey-Fuller and Doornik-Hansen tests were used. The ARMAX validation also consisted of selecting the model characterized by the lowest value of information criteria and determining ex post errors, including the mean absolute percentage error (MAPE). In addition, the nature of individual independent variables was determined, i.e. whether they were stimulants, nominants, or destimulants. The forecast made it possible to verify the possibility of meeting the assumptions of the Polish Energy Policy until 2040. It showed that if the development trends of the factors that affect wind energy do not change, it would be possible to meet the assumptions of PEP2040 regarding the dynamic development of wind farms in Poland and double the generation capacity by 2030. Analysis using the ARMAX model showed that access to raw materials such as REE, Cu, Ni, Br and Mn would have a very significant impact on the development of wind energy in Poland. Each factor of the raw material category that was introduced into the model was considered statistically significant at the significance level of α = 0.01, i.e. at the lowest acceptable risk of error. Therefore, the raw material base would be of key importance to ensure access to wind energy at the level adopted in PEP2040.

Main aim of the study was to search for possible differences in diatom colonization and their communities under the influence of glacier meltwater inflow and when unaffected by glacier meltwater, and also to define the time needed for the development of diatom communities on newly submerged substrates at small depths in Antarctica. We used artificial substrates (Plexiglass© tiles), submerged at a depth of 1 m below the sea surface at two locations at the South Bay of Livingston Island: (1) Johnsons Dock – a cove, known to receive glacier meltwater with sediments, and (2) outside the cove, generally unaffected by glacial meltwater. Samples from the natural epilithon at similar depth were also taken as a reference for diatom community structure. Statistical testing the differences between the two sites was not possible this time, but the samples allowed us to compare the sites in terms of diatom growth, species richness, diversity and evenness changes in diatom communities along the time of the experiment at both sites and with the natural epilithon at similar depths. Diatom colonization followed the three-phases scheme (colonization, logarithmic growth and equilibrium) as in other latitudes. Based on the valve density and community indices e.g. species richness, diversity (1-D) and evenness (J’), we consider that at least three weeks might be necessary to obtain sufficiently representative for the environment diatom communities on new substrates at small depths in Antarctica, in conditions similar to those of South Bay. No particular differences between the sites were noted in the colonization scheme, but the diversity (1-D) and evenness (J’) were higher at glacier influenced site, as well as the number of the valves on the substrates. Sea ice diatoms prevailed at the glacier influenced site. We suggest that species exchange between the sea ice and other hard substrates do exist, at least for some taxa, and such species might be indicative for variations in both salinity and water transparency, related to glacial meltwater inflow.