Search Results (5)

The use of non-wood forest products plays a significant role in sustainable development, especially in the context of regional development. One of the most important and promising raw materials is birch sap, which in European conditions is obtained mainly from silver birch (Betula pendula Roth). Research on the utility value of birch sap and the influence of a number of factors on its efficiency and quality has been carried out in many research centers, but so far, there are not many studies on the variability of such parameters as a function of time, taking into account the entire period of sap leakage. This research was carried out in birch stands of approximately 80 years in three forest site types: mixed coniferous forest, mixed broadleaved forest, and broadleaved forest. In each site, nine sample trees were selected using Hartig’s method. The daily and all-season sap yield obtained from individual trees was statistically characterized. The relationship between birch sap yield and select quantitative (tree height, absolute and relative crown length, and slenderness) and qualitative (forest site type, tree thickness class, and sap harvesting period) variables was examined. For the first time in the literature on the subject, there is a proposal to distinguish the phases of obtaining birch sap, which may bring new knowledge, both in relation to daily productivity and the quality of the sap. As a result, the smallest amount of sap was found in the initial leak phase, a slightly higher amount was found in the final phase, and the largest amount was found in the main phase. Regarding the forest site type and the interaction between the collection phase and forest site type, no statistically significant relationship with the average amount of obtained sap was found. Full article

We consider the effect of the external magnetic field on the in-plane conductivity in the AA-stacked bilayer graphene system in the strong excitonic condensate regime. We include the effects of the applied inter-layer electric field and the Coulomb interactions. The on-site and inter-layer Coulomb interactions were treated via the bilayer Hubbard model. Using the solutions for the physical parameters in the system, we calculate the in-plane conductivity of the bilayer graphene. By employing the Green-Kubo formalism for the polarization function in the system, we show that the conductivity in the AA bilayer system is fully controlled by the applied magnetic field. For the partial filling in the layers, the electrical conductivity is different for different spin orientations, and, at the high values of the magnetic field, only one component remains with the given spin orientation. Meanwhile, for the half-filling limit, there is no spin-splitting observed in the conductivity function. The theory evaluated here shows the new possibility for spin-controlled electronic transport in the excitonic bilayer graphene system. Full article

Dynamic climate changes are particularly apparent in polar regions. Glaciers are retreatng towards the land at a very fast pace. This study demonstrates the application of the feature tracking method in the analysis of ice flow velocity in the region of the Hornsund fiord, southern Spitsbergen, in the years 2018–2022. The calculations were based on the Geogrid and autoRIFT environments and on the Sentinel 1 images. The study also employed external data, such as a numerical terrain model and reference velocity values. The input data, e.g., the chip size and the search limit, were prepared accounting for the specific character of the investigated area. The velocities were calculated for nine biggest glaciers which terminated in the fiord. The accuracy of the results was identified by calculating the median absolute deviation (MAD) of the obtained displacement velocity values from the reference value for areas identified as stable. The study also attempted a causal analysis of the influence of weather factors on the dynamics of ice mass displacement. A systematic year-to-year decrease of the velocity was observed for the entire fiord. In the case of several glaciers, changes related to the ablation season (summer) are also clearly visible. The research results are promising and fill a research gap related to the absence of permanent monitoring and analysis of the dynamics of ice flow in polar regions. It is the first complex and precise study of glacier surface velocity changes, performed on the basis of satellite radar images for the entire Hornsund fiord. Full article

Diagnozowanie gruźlicy oparte na bakteryjnym czynniku etiologicznym ma już ponad 100-letnią historię. Nowoczesna terapia rozpoczęła się jednak dopiero po II wojnie światowej wraz z odkryciem i wprowadzeniem do terapii leków przeciwprątkowych. Przez dziesięciolecia grupy międzynarodowych specjalistów pracowały nad ustaleniem najskuteczniejszych schematów leczenia [...] Full article

The aim of the study was to compare humoral immune response against various mycobacterial anti­gens in TB and MOTT vs. healthy control group. 350 serum samples from TB patients, 20 samples from MOTT pa­tients and 58 samples from healthy donors were examined. ELISA detecting IgG, lgA and IgM against antigens: 38 kDa and 16 kDa, 38 kDa and lipoarabinomannan, and A-60 were used. Mean IgG level was higher in TB compared to healthy controls (p < 0.001). Mean IgG level against 38kDa and 38 + 16 kDa mycobacterial antigens was higher in TB than in MOTT group. Mean level of the IgG, IgA and IgM antibodies against LAM was higher in MOTT compared to TB patients. In all subgroups person-to-person heterogeneity of antigen recognition was observed. Humoral immune response to recombinant mycobacterial antigens significantly differs in TB and MOTT patients. Full article