1. Total mutual-visibility in Hamming graphsCsilla Bujtás, Sandi Klavžar, Jing Tian, 2025, original scientific article Abstract: If $G$ is a graph and $X\subseteq V(G)$, then $X$ is a total mutual-visibility set if every pair of vertices $x$ and $y$ of $G$ admits a shortest $x,y$-path $P$ with $V(P) \cap X \subseteq \{x,y\}$. The cardinality of a largest total mutual-visibility set of $G$ is the total mutual-visibility number $\mu_{\rm t}(G)$ of $G$. In this paper the total mutual-visibility number is studied on Hamming graphs, that is, Cartesian products of complete graphs. Different equivalent formulations for the problem are derived. The values $\mu_{\rm t}(K_{n_1}\,\square\, K_{n_2}\,\square\, K_{n_3})$ are determined. It is proved that $\mu_{\rm t}(K_{n_1} \,\square\, \cdots \,\square\, K_{n_r}) = O(N^{r-2})$▫, where $N = n_1+\cdots + n_r$, and that $\mu_{\rm t}(K_s^{\,\square\,, r}) = \Theta(s^{r-2})$ for every $r\ge 3$, where $K_s^{\,\square\,, r}$ denotes the Cartesian product of $r$ copies of $K_s$. The main theorems are also reformulated as Turán-type results on hypergraphs.
Keywords: mutual-visibility set, total mutual-visibility set, Hamming graphs, Turán-type problem
Published in DiRROS: 30.12.2024; Views: 16; Downloads: 9
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2. Analiza mladja na Pahernikovi posestiTomaž Rihter, Jurij Diaci, 2024, original scientific article Abstract: Kakovostno naravno pomlajevanje je ključno za sonaravno gospodarjenje, a ker gozdna inventura ne zagotavlja dovolj informacij, smo v letu 2023 izpeljali dodatno vzorčenje mladovja na mreži stalnih vzorčnih ploskev na Pahernikovi posesti. Ugotovili smo sprejemljive povprečne gostote mladja pod 130 cm višine s 15.924 osebki ha-1, mejno zadovoljive gostote mladovja nad 130 cm višine in s premerom < 5 cm z 994 osebki ha-1 in nizke gostote za mladovja med 5 in 10 cm premera z 276 osebki ha-1. Vse mladovje je v poprečju zastiralo 24 % površine tal, pritalna vegetacija pa 11 %. Razlike v gostotah in zastiranju mladovja med nadmorskimi višinami in prostorsko ločenimi deli posesti niso bile izrazite. V mladovju je prevladovala smreka (38 %), sledili sta jelka (32 %) in bukev (26 %). Visok delež jelke je bil na račun visokih gostot v višinskem razredu do 20 cm. V višjih razredih je bilo jelke vse manj, objedenost po rastlinojedi divjadi je bila intenzivnejša. Povprečno objedanje mladja do 1,3 m je znašalo 33 %, jelke pa 39 %. Izpeljana inventarizacija in analiza mladovja nakazujeta možnosti izboljševanja gozdne inventure.
Keywords: gostota in zmes drevesnih vrst, veliki rastlinojedi parkljarji, poškodbe mladovja, smrekovo-jelovo-bukovi gozdovi, jelovja, gozdna inventura
Published in DiRROS: 30.12.2024; Views: 66; Downloads: 7
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3. The effect of forest gaps on the diversity and composition of bacterial communities in mixed-type forest soils across the Carpathian mountainsNejc Suban, Olivera Maksimović, Nataša Šibanc, Tijana Martinović, Eva Dařenová, Matjaž Čater, Tine Grebenc, 2024, original scientific article Abstract: Mixed forests of European beech (Fagus sylvatica L.) and silver fir (Abies alba Mill.) play a vital ecological role in Central and South-Eastern Europe. This study investigates the diversity and composition of soil bacterial communities in these forests, focusing on rhizosphere and bulk soils under varying canopy structures. Soil samples were collected from eight sites along the Carpathian Mountains, including managed forests and the remnants of old growth. Metabarcoding of bacterial communities revealed that alpha diversity (species richness, Shannon index, and evenness) was significantly affected by sampling location but not by forest canopy structure or soil type (rhizosphere and bulk soil). The lowest bacterial diversity was found in the old-growth forest of the Beskidy region, while the highest was recorded in managed forest in Vrancea. Beta diversity analyses showed minimal variation between rhizosphere and bulk soil bacterial communities, with geographic distance being the strongest predictor of community composition. Actinobacteriota and Proteobacteria were the dominant phyla across all sites, with higher relative abundance of Actinobacteriota in all rhizosphere samples compared to bulk soil. Complex combinations of various environmental conditions at each sampling location, including soil parameters (mainly pH and C:N ratio), the age of forest gaps, the type and intensity of disturbances, and species composition of above-ground vegetation, can strongly affect soil bacterial communities. A closer examination of additional environmental variables would be necessary to better explain the observed differences in the diversity and composition of bacterial communities.
Keywords: forest gaps, forest management, soil microbiome, soil, rhizosphere, Carpathians, temperate forest
Published in DiRROS: 30.12.2024; Views: 63; Downloads: 7
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4. Modulation of the effect of cisplatin on nicotine-stimulated A549 lung cancer cells using analog of marine sponge toxin loaded in gelatin nanoparticlesAhmad Joukhan, Veno Kononenko, Marija Sollner Dolenc, Matej Hočevar, Tom Turk, Damjana Drobne, 2024, original scientific article Keywords: toxin, nAChR, nAChR antagonist, APS12-2, chemotherapeutic agent
Published in DiRROS: 24.12.2024; Views: 82; Downloads: 24
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5. The effect of different surfactants and polyelectrolytes on nano-vesiculation of artificial and cellular membranesUrška Zagorc, Darja Božič, Vesna Arrigler, Žiga Medoš, Matej Hočevar, Anna Romolo, Veronika Kralj-Iglič, Ksenija Kogej, 2024, original scientific article Keywords: extracellular vesicles, liposomes, surfactants, polyelectrolytes, static light scattering, dinamic light scattering, microcalorimetry, drug delivery, cell-to-cell communication
Published in DiRROS: 24.12.2024; Views: 92; Downloads: 30
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6. Integrated pest management strategies to control varroa mites and their effect on viral loads in honey bee coloniesJernej Bubnič, Janez Prešern, Marco Pietropaoli, Antonella Cersini, Ajda Moškrič, Giovanni Formato, Veronica Manara, Maja Ivana Smodiš Škerl, 2024, original scientific article Keywords: queen caging, trapping comb, Varroa destructor, Deformed Wing Virus, Acute Bee Paralysis Virus
Published in DiRROS: 24.12.2024; Views: 87; Downloads: 15
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7. Comparative analysis of antioxidant activity and capacity in apple varieties: Insights from stopped flow DPPH• kinetics, mass spectrometry and electrochemistryLucrezia Angeli, Francesca Populin, Ksenia Morozova, Yubin Ding, Umme Āsamā, Sara Bolchini, Anka Čebulj, Nicola Busatto, Fabrizio Costa, Giovanna Ferrentino, Matteo Scampicchio, 2024, original scientific article Keywords: Fruit quality, Polyphenols, Ascorbic acid, Free radicals, Bioactive compounds, Non-browning
Published in DiRROS: 24.12.2024; Views: 92; Downloads: 22
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8. Systematic review of sustainable forest management : integrating community forestry and agroforestry approachesKomang Ariyanto, 2024, review article Abstract: This systematic review addresses the need for integrating social, ecological, and economic dimensions into sustainable forest management to enhance resilience and sustainability. Existing research reveals a gap in understanding community involvement and governance effectiveness. The review synthesizes findings from diverse studies, focusing on community forestry and agroforestry practices. An analysis of 48 peer-reviewed articles and case studies was conducted to identify the best practices and key themes. Results indicate that robust institutions and effective governance are essential for sustainable forest management. Community engagement and education significantly enhance sustainable practices, with fiscal subsidies in forestry proving more effective than agricultural subsidies. Agroforestry emerges as a strategy that boosts agricultural income and biodiversity through improved market access. The conclusions emphasize the need to address social inequalities and urban pressures while fostering community participation for effective forest management. Recommendations include strengthening institutional frameworks, promoting education for sustainable practices, developing targeted policies that address identified barriers, and leveraging community participation in decision-making processes.
Keywords: agroforestry systems, community forestry, institutional governance, sustainable forest management
Published in DiRROS: 24.12.2024; Views: 1636; Downloads: 40
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10. Phosphorus limitation promotes soil carbon storage in a boreal forest exposed to long-term nitrogen fertilizationEtienne Richy, Tania Fort, Inaki Odriozola, Petr Kohout, Florian Barbi, Tijana Martinović, Boris Tupek, Bartosz Adamczyk, Aleksi Lehtonen, Raisa Mäkipää, Petr Baldrian, 2024, original scientific article Abstract: Forests play a crucial role in global carbon cycling by absorbing and storing significant amounts of atmospheric carbon dioxide. Although boreal forests contribute to approximately 45% of the total forest carbon sink, tree growth and soil carbon sequestration are constrained by nutrient availability. Here, we examine if long-term nutrient input enhances tree productivity and whether this leads to carbon storage or whether stimulated microbial decomposition of organic matter limits soil carbon accumulation. Over six decades, nitrogen, phosphorus, and calcium were supplied to a Pinus sylvestris-dominated boreal forest. We found that nitrogen fertilization alone or together with calcium and/or phosphorus increased tree biomass production by 50% and soil carbon sequestration by 65% compared to unfertilized plots. However, the nonlinear relationship observed between tree productivity and soil carbon stock across treatments suggests microbial regulation. When phosphorus was co-applied with nitrogen, it acidified the soil, increased fungal biomass, altered microbial community composition, and enhanced biopolymer degradation capabilities. While no evidence of competition between ectomycorrhizal and saprotrophic fungi has been observed, key functional groups with the potential to reduce carbon stocks were identified. In contrast, when nitrogen was added without phosphorus, it increased soil carbon sequestration because microbial activity was likely limited by phosphorus availability. In conclusion, the addition of nitrogen to boreal forests may contribute to global warming mitigation, but this effect is context dependent.
Keywords: carbon storage, microbial communities, boreal forest, fertilization
Published in DiRROS: 23.12.2024; Views: 97; Downloads: 31
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