721. Homomorphisms from the Coxeter graphMarko Orel, Draženka Višnjić, 2025, original scientific article Abstract: Let $S_n(\mathbb{F}_2)$ be the set of all $n\times n$ symmetric matrices with coefficients in the binary field $\mathbb{F}_2=\{0,1\}$, and let $SGL_n(\mathbb{F}_2)$ be its subset formed by invertible matrices. Let $\widehat{\Gamma}_n$ be the graph with the vertex set $S_n(\mathbb{F}_2)$ where a pair of vertices $\{A,B\}$ form an edge if and only if $rank(A-B)=1$. Similarly, let $\Gamma_n$ be the subgraph in $\widehat{\Gamma}_n$, which is induced by the set $SGL_n(\mathbb{F}_2)$. Graph $\Gamma_n$ generalizes the well-known Coxeter graph, which is isomorphic to $\Gamma_3$. Motivated by research topics in coding theory, matrix theory, and graph theory, this paper represents the first step towards the characterization of all graph homomorphisms $\Phi: \Gamma_n\to \widehat{\Gamma}_m$ where $n,m$ are positive integers. Here, the case $n=3$ is solved.
Keywords: preserver problems, symmetric matrices, invertible matrices, binary field, rank, graph homomorphisms, Coxeter graph
Published in DiRROS: 28.10.2025; Views: 212; Downloads: 116
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722. Monitoring of root-knot nematodes (Meloidogyne spp.) in Croatia (2022–2024) : occurrence, distribution and species identificationTamara Rehak Biondić, Jasna Milanović, Ivan Poje, Luka Popović, Mirjana Brmež, Barbara Gerič Stare, 2025, original scientific article Keywords: morphological identification, root-knot nematodes, nematodes, survey, molecular identification, Croatia
Published in DiRROS: 28.10.2025; Views: 227; Downloads: 50
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723. Bottom trawling and environmental variables drive the biodiversity of mediterranean demersal assemblagesDavide Agnetta, Ivano Vascotto, Diego Panzeri, Igor Celić, Cosimo Solidoro, Tomaso Fortibuoni, Saša Raicevich, Simone Libralato, 2025, original scientific article Abstract: Marine ecosystems are healthy with a high degree of biodiversity. Assessing how factors affect spatial and temporal patterns of biodiversity is an essential task for the Ecosystem Based Management approach. In this work, we investigated the effect of fisheries disturbance and ocean variables in determining α- and β-diversity of Mediterranean demersal assemblages. Generalized additive mixed models were used to explain the spatio-temporal variability of diversity indices from 2014 to 2020 in three Mediterranean subregions as a function of covariates. An in-depth analysis also made it possible to decouple the effects of bottom trawling from the other covariates. The results show that several fishing activities and environmental variables influence biodiversity, but the direction of change depends on the subregion considered. Bottom trawling instead has a quasi-linear erosion effect on α- and β-diversity in all areas. Valuable commercial species and threatened rays and sharks importantly characterized the sites with low fishing impact. Results are a step towards the development of conservation and management strategies, particularly in the context of the Marine Strategy.
Keywords: biodiversity, fishing, Mediterranean sea, marine strategy
Published in DiRROS: 28.10.2025; Views: 235; Downloads: 99
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724. Decomposition of Whittaker’s gamma diversity : a novel way combining entropies and divergencesIvano Vascotto, Davide Agnetta, 2025, original scientific article Abstract: Accurate, standardized, and comparable methods for estimating biodiversity are crucial in ecology to properly assess and monitor the health of communities. Special cases of generalized entropy are commonly used to estimate alpha diversity. The related concept of generalized divergence can be used to estimate the beta diversity. Using cross entropy notion, we propose a modular decomposition of gamma diversity by using entropy and divergence functions. We prove that if alpha is Shannon entropy and beta is Kullback-Liebler divergence, the classical Whittaker’s gamma diversity is mathematically decomposed via our proposed local gamma index. To show the ecological application of this index and its generalization we compute the local gamma of several orders using a real large biological dataset. The index is discussed in detail for two limit cases, one where the contribution of rare species is the highest and one where richness and evenness are balanced. The index defines a gradient from communities that are dominated by a few common species toward samples shared among several uncommon ones. Our findings support divergence-based measures as practical estimators of beta diversity. Also, the framework here proposed, based on entropy, divergences and cross-entropies, allows us to compute the classic gamma diversity while providing components that are independent, comparable, self-reliant and pointwise distributed.
Keywords: biodiversity, entropy, ecology, computational modelling
Published in DiRROS: 28.10.2025; Views: 202; Downloads: 114
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725. Asymmetry of copulas with a given opposite diagonal sectionDamjana Kokol-Bukovšek, Blaž Mojškerc, Nik Stopar, 2025, original scientific article Abstract: In this paper we investigate bivariate copulas with a given opposite diagonal section. We determine the exact lower bound for all such copulas and derive an explicit formula for the maximal asymmetry for copulas with a given opposite diagonal section. As a special case, we consider the situation when the opposite diagonal section is symmetric and unimodal, which is true in many applications. To obtain our results, we also calculate the maximal asymmetry of all distributions with fixed marginals, which is an interesting result by itself.
Keywords: mathematical statistics, mathematical analysis, mathematical methods, copulas, opposite diagonal section, asymmetry, distribution
Published in DiRROS: 28.10.2025; Views: 187; Downloads: 110
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726. Predstavitev Priročnika o načrtovanju ravnanja z raziskovalnimi podatkiSonja Bezjak, Maja Zagorščak, Irena Vipavc Brvar, Anže Županič, 2025, other monographs and other completed works Abstract: Predstavitev je predstavila zasnovo in vsebino novega spletnega Priročnika o načrtovanju ravnanja z raziskovalnimi podatki (2025) ter pokazala njegovo praktično uporabo na konkretnih primerih iz naravoslovja in družboslovja.
Keywords: načrt ravnanja z raziskovalnimi podatki, odprti podatki, podatkovna objava, načela FAIR, odprta znanost
Published in DiRROS: 28.10.2025; Views: 270; Downloads: 129
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728. Simple and fast wettability control of aminosilanized surfaces with carboxylic acidsAndraž Černoga, Jelena Papan Djaniš, Darja Lisjak, Jernej Iskra, Griša Grigorij Prinčič, 2025, original scientific article Keywords: reverse wettability, aminosilane, ion pair, self-cleaning surface
Published in DiRROS: 27.10.2025; Views: 224; Downloads: 117
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730. Mentoring programmes for women in research and academia in Europe : version v1Aleksandra Thomson, María López Belloso, Theranda Beqiri, Ana Rotter, Colette Guillopé, Jasmin Schomakers, Anna Szlavi, Ermira H. Kalaj, Maria Bostenaru Dan, Fatma Demir Korkmaz, 2025, complete scientific database of research data Abstract: This dataset documents an exploratory mapping of mentorship programmes designed to support women and other marginalised groups within academic and research environments across Europe and neighbouring regions. The initiative was led by members of VOICES Working Group 1 (WG1), who contributed insights based on their local institutional knowledge. Rather than aiming for statistical representativeness, the mapping sought to capture diverse, context-specific examples of mentoring practices and structures.
Keywords: mentoring programmes, women in research, gender equality, data, European Union
Published in DiRROS: 27.10.2025; Views: 194; Downloads: 92
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