1431. |
1432. Researching the change in the weight of split oak firewood due to different drying methodsAmina Gačo, 2021, objavljeni znanstveni prispevek na konferenci Povzetek: In this paper, the influences of stacking methods and drying places of split oak firewood in winter conditions (Quercus cerris) have been experimentally and theoretically investigated, due to the great importance of use in heating with such wood. The research was conducted on a sample of 48 pieces of logs with bark made of freshly cut oak. The logs were obtained by mechanized technology with the help of grafting by a hydraulic splitter and a chainsaw. Each log was measured for a research length of 0.30 m, marked with numbers 1-24. On each log, the weight was measured on a scale of 5 kg with an accuracy of 0.5 grams. Drying of logs was performed in two places. The first drying place was in outdoor conditions, sheltered from the snow and ventilated. The second place was indoors, at approximately constant room temperature. The logs were stacked in a crossed way for better air circulation. They were dried between 15/12/2020 and 15/02/2021, a total of 62 days. The average initial weight of logs dried in the facility was 1130.3 g, in the dried state the average weight was 952.87 g, which represented 84.3% of the original weight. The average initial weight of logs dried in outdoor conditions was 1192.125 g, in the dried state 1076.37 g, which represented 90.29% of the original weight. The average initial water content in the logs dried in the facility was 37.9%, in the dried state it was 27.5%. For logs dried in outdoor conditions, the average initial amount of water was 36.6%, in the dried state the average amount of water was 31.2%. Ključne besede: weight, drying methods, splitting firewood, oak, stacking methods Objavljeno v DiRROS: 09.04.2024; Ogledov: 656; Prenosov: 480
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1433. Bio-based tannin-furanic-silk adhesives : applications in plywood and chemical cross-linking mechanismsEmanuele Cesprini, Johannes Jorda, Marco Paolantoni, Luca Valentini, Primož Šket, Valerio Causin, Diana E. Bedolla, Michela Zanetti, Gianluca Tondi, 2023, izvirni znanstveni članek Objavljeno v DiRROS: 09.04.2024; Ogledov: 363; Prenosov: 137
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1434. Effects of high-intensity interval training (HIIT) on physical performance in female team sports : a systematic reviewMima Stanković, Dusan Djordjevic, Nebojša Trajković, Zoran Milanović, 2023, pregledni znanstveni članek Povzetek: Abstract Background There is limited information regarding adaptation of HIIT in female athletes which is important since the adaptation to HIIT may be diferent compared to male athletes. Therefore, the aim of this systematic review was to summarize the efects of HIIT on physical performance in female team sports athletes. Methods The following databases Google Scholar, PubMed, Web of Science, Cochrane Library, ProQuest and Science Direct were searched prior to September 2nd, 2022. The inclusion criteria were longitudinal studies written in English, elite, sub-elite or college female team sports participants, and HIIT intensity had to be at 80–100% maximal heart rate. There were no exclusion criteria regarding the age of the participants or their training experience. The primary outcome measures were maximal oxygen uptake (VO2max), repeated sprint ability (RSA), change of direction speed, speed, explosive strength and body composition. Results A total of 13 studies met the inclusion criteria, with a total of 230 participants. HIIT improved VO2max in fve studies (ES from 0.19 to 1.08), while three studies showed improvement in their RSA (ES from 0.32 to 0.64). In addition, change of direction speed was improved in fve studies (ES from 0.34 to 0.88), while speed improved in four studies (ES from 0.12 to 0.88). Explosive strength results varied (ES from 0.39 to 1.05), while in terms of body composition, the results were inconsistent through observed team sports. Conclusion HIIT has signifcant efects on VO2max, RSA, change of direction speed, speed and explosive strength in female team sports, regardless of the competition level. Ključne besede: interval training, output, VO2max, physical fitness Objavljeno v DiRROS: 09.04.2024; Ogledov: 379; Prenosov: 258
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1435. Graphs with equal Grundy domination and independence numberGábor Bacsó, Boštjan Brešar, Kirsti Kuenzel, Douglas F. Rall, 2023, izvirni znanstveni članek Povzetek: The Grundy domination number, ${\gamma_{\rm gr}}(G)$, of a graph $G$ is the maximum length of a sequence $(v_1,v_2,\ldots, v_k)$ of vertices in $G$ such that for every $i\in \{2,\ldots, k\}$, the closed neighborhood $N[v_i]$ contains a vertex that does not belong to any closed neighborhood $N[v_j]$, where $jKljučne besede: Grundy domination, independence number, upper domination number, bipartite graphs Objavljeno v DiRROS: 09.04.2024; Ogledov: 288; Prenosov: 220
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1436. Mixed signals of environmental change and a trend towards ecological homogenization in ground vegetation across different forest typesJanez Kermavnar, Lado Kutnar, 2024, izvirni znanstveni članek Povzetek: Forest ground vegetation may serve as an early warning system for monitoring anthropogenic global-change impacts on temperate forests. Climate warming may induce a decline of cool-adapted species to the benefit of more thermophilous plants. Nitrogen deposition has been documented to potentially result in soil eutrophication or acidification, which can increase the proportion of species with higher nutrient requirements and species impoverishment caused by competitive exclusion. Abiotic forest disturbances are changing the light conditions in the forest understorey environment. In this resurvey study, we tested the magnitude and direction of change in alpha (species richness) and beta (within-site dissimilarity) diversity and composition of forest ground vegetation in forests of different types in Slovenia over fifteen years. Using plant-derived characteristics (Ellenberg-type indicator values) and by testing a priori predictions concerning expected effects of environmental drivers, we show that the magnitude and direction of forest ground vegetation diversity and floristic changes varies greatly between forest sites. Divergent responses at different sites resulted in low net change of alpha and beta diversity and a weak overall environmental signal. The largest decrease in species number was observed in lowland oak-hornbeam forests, which were also among the sites with the greatest compositional shifts. Changes in beta diversity did not show any consistent trend, and anticipated floristic convergence was not confirmed when all sites were considered. Thermophilization was mainly detected in montane beech sites and alpine spruce forests whereas eutrophication signal was most significant on nutrient-poor sites. Vegetation responses were strongly dependent on initial site conditions. Shrinkage of ecological gradients (process of ecological homogenization) suggests that sites positioned at the ends of the gradients are losing their original ecological character and are becoming more similar to mid-gradient sites that generally exhibit smaller changes. Our results point to the importance of local stand dynamics and overstorey disturbances in explaining the temporal trends in forest ground vegetation. Ground vegetation in Slovenian forests is changing in directions also dictated by multiple regional and global change drivers. Ključne besede: vegetation resurvey, thermophilization, eutrophication, forest disturbances, alpha and beta diversity, initial site conditions, ICP-Forests network Objavljeno v DiRROS: 09.04.2024; Ogledov: 457; Prenosov: 239
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1437. Wandering domains arising from Lavaurs maps with Siegel disksMatthieu Astorg, Luka Boc Thaler, Han Peters, 2023, izvirni znanstveni članek Povzetek: The first example of polynomial maps with wandering domains was constructed in 2016 by the first and last authors, together with Buff, Dujardin and Raissy. In this paper, we construct a second example with different dynamics, using a Lavaurs map with a Siegel disk instead of an attracting fixed point. We prove a general necessary and sufficient condition for the existence of a trapping domain for nonautonomous compositions of maps converging parabolically towards a Siegel-type limit map. Constructing a skew-product satisfying this condition requires precise estimates on the convergence to the Lavaurs map, which we obtain by a new approach. We also give a self-contained construction of parabolic curves, which are integral to this new method. Ključne besede: Fatou sets, holomorphic dynamics, parabolic implosion, polynomial mappings, skew-products, wandering Fatou components, parabolic curves, nonautonomous dynamics Objavljeno v DiRROS: 09.04.2024; Ogledov: 508; Prenosov: 142
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1438. Depth of SCUBA diving affects cardiac autonomic nervous systemMarina Vulić, Branislav Milovanovic, Ante Obad, Duška Glavaš, Igor Glavičič, Damir Zubac, Maja Valic, Zoran Valić, 2024, pregledni znanstveni članek Povzetek: The present study investigated the influence of SCUBA dives with compressed air at depths of 10 and 20 m on ECG-derived HRV parameters in apparently healthy individuals. We hypothesized that cardiac sympathetic activity (measured by HRV parameters) adapts proportionally to diving depth, and that both time- and frequency-domain parameters are sensitive enough to track changes in cardiac ANS function during diving activities and subsequently during the recovery period. Eleven healthy middle-aged recreational divers (nine men and two women, age 43 ± 8, all nonsmokers) volunteered to participate in the present study. The participants (all open-circuit divers) were equipped with dry suits and ECG Holter devices and were later randomly assigned to dive pairs and depths (10 m vs. 20 m), and each participant served as his or her own control. No interaction effects (diving depth x time epoch) were found for the most commonly used HRV markers. More precisely, in response to two different diving protocols, a significant post hoc effect of time was observed for HR and SDNN, as these parameters transiently decreased during the dives and returned to baseline after ascent (p < 0.001). The ULF, VLF (p < 0.003), TP, and LF parameters decreased significantly during the dives, while HF significantly increased (p < 0.003). SCUBA diving apparently challenges the cardiac ANS, even in healthy individuals. The observed changes reveal possible underwater methods of influencing the parasympathetic activity of the heart depending on the depth of the dive. These results identify autonomic nervous system markers to track the cardiovascular risk related to diving and point to the possibility of tracking cardiovascular system benefits during underwater activities in selected patients Ključne besede: autonomic nervous system, diving, parasympathicus, cardiovascular risk Objavljeno v DiRROS: 09.04.2024; Ogledov: 344; Prenosov: 189
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1440. Injective coloring of graphs revisitedBoštjan Brešar, Babak Samadi, Ismael G. Yero, 2023, izvirni znanstveni članek Povzetek: An open packing in a graph $G$ is a set $S$ of vertices in $G$ such that no two vertices in $S$ have a common neighbor in $G$. The injective chromatic number $\chi_i(G)$ of $G$ is the smallest number of colors assigned to vertices of ▫$G$▫ such that each color class is an open packing. Alternatively, the injective chromatic number of $G$ is the chromatic number of the two-step graph of $G$, which is the graph with the same vertex set as $G$ in which two vertices are adjacent if they have a common neighbor. The concept of injective coloring has been studied by many authors, while in the present paper we approach it from two novel perspectives, related to open packings and the two-step graph operation. We prove several general bounds on the injective chromatic number expressed in terms of the open packing number. In particular, we prove that $\chi_i(G) \ge \frac{1}{2}\sqrt{\frac{1}{4}+\frac{2m-n}{\rho^{o}}}$ holds for any connected graph $G$ of order $n\ge 2$, size $m$, and the open packing number ${\rho^{o}}$, and characterize the class of graphs attaining the bound. Regarding the well known bound $\chi_i(G)\ge \Delta(G)$, we describe the family of extremal graphs and prove that deciding when the equality holds (even for regular graphs) is NP-complete, solving an open problem from an earlier paper. Next, we consider the chromatic number of the two-step graph of a graph, and compare it with the clique number and the maximum degree of the graph. We present two large families of graphs in which $\chi_i(G)$ equals the cardinality of a largest clique of the two-step graph of $G$. Finally, we consider classes of graphs that admit an injective coloring in which all color classes are maximal open packings. We give characterizations of three subclasses of these graphs among graphs with diameter 2, and find a partial characterization of hypercubes with this property. Ključne besede: two-step graph of a graph, injective coloring, open packing, hypercubes Objavljeno v DiRROS: 09.04.2024; Ogledov: 325; Prenosov: 140
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