THE CHARACTERISTICS OF Al-Si COATING ON STEEL 22MnB5 DEPENDING ON THE HEAT TREATMENT

The coating on the 22MnB5 steel is intended to protect it against oxidation during the forming process. This steel is hot-pressed. A preheating before the pressing and subsequent hardening in the tool affects the properties of the AlSi coating. This study summarizes the results of investigating the effect of heat treatment parameters on the formation of intermetallics in the AlSi coating. The chemical analysis of the coating was performed by the EDX and EBSD method and the mechanical properties were determined by the Hysitron TI 950 TriboIndenter™ system. The result of this study is that, due to a diffusion during the heat treatment, the brittle coating was transformed into a tougher phase

Evaluation of Spatio-Temporal Patterns of Predation Risk to Forest Grouse Nests in the Central European Mountain Regions

We evaluated the spatiotemporal patterns of predation risk on black grouse nests using artificial nests that were monitored by camera traps in mountain areas with a small extant (Ore Mts.) and already extinct (Jeseníky Mts.) black grouse population. The overall predation rate of artificial nests was 56% and we found significant differences in survival rate courses over time between both study areas (68% Ore Mts. vs. 41%, Jeseníky Mts.). Within the time required for successful egg incubation (25 days), nest survival probability was 0.32 in the Ore Mts. and 0.59 in Jeseníky Mts. The stone marten (Martes foina) was the primary nest predator in both study areas (39% in total), followed by common raven (Corvus corax, 25%) and red fox (Vulpes vulpes, 22%). The proportion of depredated nests did not differ between habitat types (i.e., open forest interior, clearing, forest edge), but we recorded the effect of interaction of study area and habitat. In Ore Mts., the main nest predator was common raven with seven records (37%). The Eurasian jay (Garrulus glandarius) was responsible for most predation attempts in Jeseníky Mts. (five records, i.e., 83%), while in the Ore Mts., most predation attempts were done by red fox (six records, i.e., 38%publishedVersio

Thermus and the Pink Discoloration Defect in Cheese

peer-reviewedA DNA sequencing-based strategy was applied to study the microbiology of Continental-type cheeses with a pink discoloration defect. The basis for this phenomenon has remained elusive, despite decades of research. The bacterial composition of cheese containing the defect was compared to that of control cheese using 16S rRNA gene and shotgun metagenomic sequencing as well as quantitative PCR (qPCR). Throughout, it was apparent that Thermus, a carotenoid-producing genus, was present at higher levels in defect-associated cheeses than in control cheeses. Prompted by this finding and data confirming the pink discoloration to be associated with the presence of a carotenoid, a culture-based approach was employed, and Thermus thermophilus was successfully cultured from defect-containing cheeses. The link between Thermus and the pinking phenomenon was then established through the cheese defect equivalent of Koch’s postulates when the defect was recreated by the reintroduction of a T. thermophilus isolate to a test cheese during the manufacturing process. IMPORTANCE Pink discoloration in cheese is a defect affecting many cheeses throughout the world, leading to significant financial loss for the dairy industry. Despite decades of research, the cause of this defect has remained elusive. The advent of high-throughput, next-generation sequencing has revolutionized the field of food microbiology and, with respect to this study, provided a means of testing a possible microbial basis for this defect. In this study, a combined 16S rRNA, whole-genome sequencing, and quantitative PCR approach was taken. This resulted in the identification of Thermus, a carotenoid-producing thermophile, in defect-associated cheeses and the recreation of the problem in cheeses to which Thermus was added. This finding has the potential to lead to new strategies to eliminate this defect, and our method represents an approach that can be employed to investigate the role of microbes in other food defects of unknown origin.Teagasc Walsh Fellowship Programm

Digital skills among youth: a dataset from a three-wave longitudinal survey in six European countries

This dataset provides longitudinal survey data from a European project, ySKILLS, which was focused on the role of digital skills in youths’ development. It contains data from 10,821 participants from Grades 6-10 (in Wave 1) in Estonia, Finland, Germany, Italy, Poland, and Portugal. The data was collected between Spring 2021 and Spring 2023, the participants were recruited through schools, where the data collection also took place, except for online data collections due to restrictions caused by COVID-19. The dataset is novel in its multidimensional approach to the construct of digital literacy. It provides insight into the development of digital skills in youth and the role of digital skills and internet usage in youths’ positive and negative online experiences and wellbeing. It also contains data that allows for the analysis of the role of digital skills in class networks. The data are beneficial for researchers interested in the examination of youths’ online skills, internet usage, online experiences, and wellbeing from a longitudinal perspective

Morphological variability of birch genus (Betula L.) in chosen regions of the Czech Republic with a focus on tetraploid taxa

The aim of this work is to propose reliable method for distinguishing between diploid (2n) and tetraploid (4n) taxa of the genus Betula L., based on leaf measurements. These measurements are realized by common tools, such as ruler or protractor. Main advantage of these methods is that they can be applied even in the field. The further aim of work is to describe and evaluate genetic variability within tetraploid taxa, whose taxonomic relationships are still unclear and under discussions. For statistical analysis, 97 individuals from 6 localities within Šumava region were selected and 4 leaves from every individual were analysed. In total, 20 parameters were measured on every leaf (16 quantitative and 4 qualitative). Each individual was also analysed by flow cytometry method to determine real genome size (ploidy). Differences in selected parameters between individuals with different ploidy were statistically tested. Significant results were observed in 12 of 16 quantitative and 2 of 4 qualitative parameters. For real ploidy prediction, the classification function was designed, whose reliability was 96 % for the primary data. The reliability of classification function was verified on samples from three different regions within the Czech Republic and compared with functions suggested by other authors. Function designed in this work was able to correctly determine real ploidy in 89 %, which is the most of all compared functions. Genetic variability, especially within tetraploid taxa is mentioned in relation to other author's previous studies. Distinguishing between B. pubescens and B. carpatica was not possible using selected genetic markers. Genetic conformity of these taxa is also mentioned in publications of foreign authors, as contrasted to Czech literature, which generally distinguishes B. pubescens and B. carpatica as separated species

Genetic and morphometric variability between populations of Betula ×oycoviensis from Poland and Czechia: A revised view of the taxonomic treatment of the Ojców birch.

Birches are generally known for their high genetic and morphological variability, which has resulted in the description of many species. Ojców birch was described in 1809 by Willibald Suibert Joseph Gottlieb Besser in Poland. Since then, several studies assessing its taxonomy were conducted. Today, various authors present Ojców birch at different taxonomic ranks. In Czechia, the Ojców birch is classified a critically endangered taxon and confirmed at one locality consisting of several tens of individuals. However, before a strategy for its conservation can be applied, we consider it necessary to assess the taxonomic position of the endangered Czech population and to evaluate its relationship to the original Polish population. This study aimed to evaluate the morphometric and genetic variability between populations of B. ×oycoviensis in Poland and the Czechia and their relationship to regional populations of B. pendula, one of the putative parental species of the Ojców birch. Altogether, 106 individuals were sampled, including the holotype of B. szaferi, the second putative parental species of B. ×oycoviensis, received from the herbarium of W. Szafer, which is deposited at the Institute of Botany in Kraków. Morphological analyses identified differences in leaves between B. ×oycoviensis and B. pendula. However, no significant differences were found in genome size between selected taxa/working units except for B. pendula sampled in Czechia. The identified difference of the Czech population of B. pendula is probably caused by population variability. Genetic variability between all the taxa under comparison, regardless of their origin, was also very low; only the benchmark taxa (B. nana and B. humilis) clearly differed from all samples analyzed. The results indicate minute morphological and negligible genetic variability between the Czech and Polish populations of B. ×oycoviensis. In light of our results, the classification of B. ×oycoviensis as B. pendula var. oycoviensis seems more accurate than all hitherto presented alternatives (e.g. B. ×oycoviensis as a separate species)

Carbon sequestration in soil following afforestation of former agricultural land in the Czech Republic

Soil organic carbon (SOC) is a great component of the global carbon cycle and plays significant role in terms of climatic changes and agricultural land-use. An important management concern is the extent of SOC stocks sequestration when farmland is converted to forest stands. We have reviewed the literature about changes in SOC stock in relation to altitude and stand age and sought differences between former agricultural land and origin forest stands. Accumulation of SOC was monitored in 17 examples (41 samples) in 9 locations across the all Czech Republic with focus on the main tree species Norway spruce (Picea abies [L.] Karst.). Results showed a significant increase of SOC stock in an afforested farmland with increasing stand age. Another factor was the altitude. With increasing altitude, the carbon stock in our model gradually decreased. From the data analyzed comparing forest stand and former agricultural land, similar carbon sequestration was documented for both variants with higher SOC for forest stands. However, other conditions affecting SOC stock should be taken into consideration, especially silvicultural management, topography, disturbances, soil properties and cultivation. The general tendencies of SOC changes at the investigated sites are comparable to those in other studies across the Europe

Does shelterwood regeneration on natural Scots pine sites under changing environmental conditions represent a viable alternative to traditional clear-cut management?

In the context of climate change, the crucial question is how silvicultural treatments should be modified, in order to reach favourable conditions for initiating natural regeneration of forest stands. The aim of the study was to evaluate the influence of clear-cutting, basal area reduction (0.4, 0.6 and 0.8) and soil preparation (milling cutter, forestry mulcher, brush rake and control variant without soil preparation) on the regeneration of Scots pine (Pinus sylvestris L.) in the conditions of natural pine sites (Northern Bohemia). Seedling numbers, heights and crown widths were recorded on transects representing all combinations of stand densities treatments and soil preparations variants three years after the silvicultural operations. Seed traps were installed to determine the numbers of seeds from 2016 to 2018. Soil water potential (Delmhorst Instrument Company) and soil temperature (sensor Pt1000 A–class sensors, EMS Brno) were measured. All variants of soil preparation had higher numbers of seedlings compared to control variant. When comparing stand densities, total numbers of seedlings were the highest in stand density 0.4 (cutter 32,402 ± 34,208 S.D. ind.ha−1; mulcher 26,832 ± 24,088 S.D. ind.ha−1; rake 24,496 ± 22,913 S.D. ind.ha−1). This stand density was also beneficial with respect to seed numbers, seedling characteristics and soil moisture and temperature characteristics. We conclude that shelterwood regeneration on natural Scots pine sites is promising silvicultural approach and may become an important tool in mitigating negative effects of climate change in the future

Wear modelling of soil ripper tine in sand and sandy clay by discrete element method

Wear and friction cause huge economic losses in the agriculture and mining industries. Wear simulations of working elements, materials, and surfaces that can reduce downtime and economic losses. This work proposes the use a cone penetration resistance measurement result as option to determine movement resistance of soil ripper tine by the discrete element method. It allows avoiding mechanical properties investigation of soil. Simulation made in sand and sandy clay helps to compare wear track of tine wear plates with actual wear. The actual wear was evaluated by 3D scanning of a soil ripper tine wear plates made from tungsten carbide and cobalt alloy and compared with simulated tines. Wear loss expressed as loss of area at the cross-section of tine wear plate. The maximum wear loss of scanned ripper wear plate at 0e150 mm working depth is 1.8% and simulatedin- sand and simulated-in-sandy-clay 1.2 and 1.7%. The maximum actual wear loss caused 57.9% wear loss of cross-section area at 150e204 mm working depth. Simulation in sand and simulation in sandy clay soil 6.9 and 9% caused by lower soil resistance than in field experiments. Simulations in sandy clay soil increased the draft force by 3.9 and 2.8 times that in the sand, at 0e200 mm depth, for tine parts to account for the stiffness fraction of sandy clay soil. As an alternative, tine wear evaluation is also suggested from shear energy valuesVytauto Didžiojo universitetasŽemės ūkio akademij

Are clearcut borders an effective tool for Scots pine (Pinus sylvestris L.) natural regeneration?

Aim of the study: To describe the effect of stand edge after clearcut on the process of Scots pine (Pinus sylvestris L.) natural regeneration along the edge-to-interior gradient. The density, height, horizontal structure and quality of natural regeneration was evaluated.Area of the study: Kokořínsko Protected Landscape Area, Northern Bohemia (Czech Republic). The study sites naturally host Scots pine Pinetum oligotrophicum with cover of Vaccinium myrtillus L. and Vaccinium vitis-idaea L. in the herbal storey.Material and methods: Two 40 × 40 m permanent research plots were situated at the forest edge, two adjacent plots were established within the forest stand as control plots. Differences in regeneration characteristics were tested by analysis of variance (ANOVA) followed by the Tukey HSD test. Interactions between regeneration characteristics and the distance from the edge were evaluated by Pearson correlation. The relationship between the top storey and natural regeneration was depicted by pair-correlation function. Principal components analysis was carried out to assess overall data structure.Main results: Generally, the further from the stand edge, the lower natural regeneration density (r ≤ -0.64, p<0.001), mean height (r ≤ -0.54, p<0.001) and the best-quality promising individuals (r = -0.40, p<0.05) were found, whereas significant influence on overall average pine quality was not observed. The highest regeneration density (15,250 pcs/ha) was reached at a distance of 5-10 m from the stand edge.Research highlights: The forest edge interior can become favourable location for natural regeneration and can be implemented into traditional regeneration approaches in pine regions