1. Collective dynamics of swarmalators with higher-order interactionsMd Sayeed Anwar, Gourab Kumar Sar, Matjaž Perc, Dibakar Ghosh, 2024, original scientific article Abstract: Higher-order interactions shape collective dynamics, but how they affect transitions between different states in swarmalator systems is yet to be determined. To that effect, we here study an analytically tractable swarmalator model that incorporates both pairwise and higher-order interactions, resulting in four distinct collective states: async, phase wave, mixed, and sync states. We show that even a minute fraction of higher-order interactions induces abrupt transitions from the async state to the phase wave and the sync state. We also show that higher-order interactions facilitate an abrupt transition from the phase wave to the sync state bypassing the intermediate mixed state. Moreover, elevated levels of higher-order interactions can sustain the presence of phase wave and sync state, even when pairwise interactions lean towards repulsion. The insights gained from these findings unveil self-organizing processes that hold the potential to explain sudden transitions between various collective states in numerous real-world systems. Keywords: collective dynamics, nonlinear oscillator, higher-order interactions, complex network, statistical physics Published in DKUM: 07.05.2025; Views: 0; Downloads: 0
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2. Izbira habitata evropskega bobra Castor fiber (Rodentia: Castoridae) na Goričkem (severovzhodna Slovenija)Laura Kološa, Franc Janžekovič, Tina Klenovšek, 2024, original scientific article Abstract: Evropski bober je v Sloveniji in večjem delu Evrope v začetku 20. stoletja veljal za izumrlo vrsto. Ob koncu 20. stoletja se je po številnih reintrodukcijah in uveljavitvi ohranitvenih ukrepov ponovno razširil. V Sloveniji se je vnovič naselil leta 1998, na Goričkem leta 2016. V zimi 2021/22 smo na Goričkem popisali šest vodnih teles, na katerih je bilo med letoma 2016 in 2020 potrjeno pojavljanje te vrste. Namen popisa je bil ugotoviti značilnosti bobrovega habitata na Goričkem glede na ključne okoljske dejavnike, ki mu omogočajo preživetje. Zaradi zgodnje faze naselitve smo domnevali, da je bober za svoj teritorij izbral optimalne habitate. Na izbranih odsekih vodnih teles smo popisali 82 ploskev. Aktivnost bobra je bila potrjena na 71 % ploskev s stoječo in 26 % ploskev s tekočo vodo. Najpogostejši tip kopenskega habitata so bile njive. Gozd je pokrival le 18 % ploskev. Bober je bil najpogosteje zabeležen prav na ploskvah z gozdom (73 %). Brežine vodnih teles so bile v glavnem zelo strme (> 60°). Sledovi bobra so bili najpogosteje najdeni na brežinah z višino do vključno 1 m, naklonom 30°–60° in povprečno 500 m oddaljenostjo od naselij. Vodotoki, ki jih je na Goričkem naselil bober, so razmeroma ozki in plitki, a jih bober kljub temu naseljuje. Najpomembnejši okoljski dejavnik za bobre je razpoložljivost ustrezne lesne vegetacije, s katero se hrani predvsem jeseni in pozimi. Poznavanje značilnosti in izbire habitata je pomembno za varstveno upravljanje in monitoring bobra na Goričkem in v Sloveniji. Keywords: Castor fiber, evropski bober, ekološke spremenljivke Published in DKUM: 06.05.2025; Views: 0; Downloads: 1
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3. Discrete memristive Hindmarsh-Rose neural model with fractional-order differencesFatemeh Parastesh, Karthikeyan Rajagopal, Sajad Jafari, Matjaž Perc, 2025, original scientific article Abstract: Discrete systems can offer advantages over continuous ones in certain contexts, particularly in terms of simplicity and reduced computational costs, though this may vary depending on the specific application and requirements. Recently, there has been growing interest in using fractional differences to enhance discrete models' flexibility and incorporate memory effects. This paper examines the dynamics of the discrete memristive Hindmarsh-Rose model by integrating fractional-order differences. Our results highlight the complex dynamics of the fractional-order model, revealing that chaotic firing depends on both the fractional-order and magnetic strength. Notably, certain magnetic strengths induce a transition from periodic firing in the integer-order model to chaotic behavior in the fractional-order model. Additionally, we explore the dynamics of two coupled discrete systems, finding that electrical coupling leads to the synchronization of chaotic dynamics, while chemical coupling ultimately results in a quiescent state. Keywords: memristive Hindmarsh-Rose model, discrete systems, fractional-order differences Published in DKUM: 06.05.2025; Views: 0; Downloads: 0
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4. Structural roles and gender disparities in corruption networksArthur A. B. Pessa, Alvaro F. Martins, Mônica V. Prates, Sebastián Gonçalves, Cristina Masoller, Matjaž Perc, Haroldo V. Ribeiro, 2025, original scientific article Abstract: Criminal activities are predominantly due to males, with females exhibiting a significantly lower involvement, especially in serious offenses. This pattern extends to organized crime, where females are often perceived as less tolerant to illegal practices. However, the roles of males and females within corruption networks are less understood. Here, we analyze data from political scandals in Brazil and Spain to shed light on gender differences in corruption networks. Our findings reveal that females constitute 10% and 20% of all agents in the Brazilian and Spanish corruption networks, respectively, with these proportions remaining stable over time and across different scandal sizes. Despite this disparity in representation, centrality measures are comparable between genders, except among highly central individuals, for which males are further overrepresented. Additionally, gender has no significant impact on network resilience, whether through random dismantling or targeted attacks on the largest component. Males are more likely to be involved in multiple scandals than females, and scandals predominantly involving females are rare, though these differences are explained by a null network model in which gender is randomly assigned while maintaining gender proportions. Our results further reveal that the underrepresentation of females partially explains gender homophily in network associations, although in the Spanish network, male-to-male connections exceed expectations derived from a null model. Keywords: gender disparity, corruption network, political scandal, social physics, social physics Published in DKUM: 25.04.2025; Views: 0; Downloads: 0
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5. EEG-based finger movement classification with intrinsic time-scale decompositionMurside Degirmenci, Yilmaz Kemal Yuce, Matjaž Perc, Yalcin Isler, 2024, original scientific article Keywords: brain-computer interfaces, electroencephalogram, feature reduction, machine learning, finger movements classification, time series analysis Published in DKUM: 16.04.2025; Views: 0; Downloads: 0
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6. Pupal development and adult acclimation temperatures influence the cold and heat tolerance in Tenebrio molitor (Coleoptera: Tenebrionidae)Jan Podlesnik, 2025, original scientific article Abstract: Temperature plays a crucial role in shaping the biology of insects. Developmental temperature and acclimation temperatures influence their ability to cope with extreme thermal conditions. This study investigates the effects of developmental temperatures during the pupal stage and adult acclimation temperatures on the thermal tolerance of Tenebrio molitor Linnaeus, 1758. We investigated cold tolerance based on chill-coma recovery time and heat tolerance based on heat knockdown time. Beetles were reared at five developmental temperatures (16, 21, 25, 30 and 35 °C) and later exposed to corresponding adult acclimation temperatures. From developmental temperatures of 21 and 30 °C, the group of beetles was subjected to different temperatures to induce adult acclimation at a different temperature than the developmental temperature. In cold-tolerance tests, beetles reared at lower temperatures showed better recovery from chill coma, while beetles reared at higher temperatures showed greater resistance to heat shock. Adult beetles acclimated to lower temperatures showed better cold tolerance, while those acclimated to higher temperatures performed better in the heat tolerance test. Interestingly, the developmental temperatures during the pupal stage also contributed to resistance, particularly in the heat tolerance test. However, pupal stage temperatures had no effect on cold-shock resistance, as indicated by chill-coma recovery time. The results could provide insights into the rearing of T. molitor. Keywords: adult acclimation, cold tolerance, developmental acclimation, heat knockdown, heat tolerance, Tenebrio molitor, thermal tolerance, chill coma, yellow mealworm Published in DKUM: 15.04.2025; Views: 0; Downloads: 1
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8. Commercial SARS-CoV-2 targeted, protease inhibitor focused and protein–protein interaction inhibitor focused molecular libraries for virtual screening and drug designSebastjan Kralj, Marko Jukič, Urban Bren, 2022, review article Abstract: Since December 2019, the new SARS-CoV-2-related COVID-19 disease has caused a global
pandemic and shut down the public life worldwide. Several proteins have emerged as potential
therapeutic targets for drug development, and we sought out to review the commercially available
and marketed SARS-CoV-2-targeted libraries ready for high-throughput virtual screening (HTVS).
We evaluated the SARS-CoV-2-targeted, protease-inhibitor-focused and protein–protein-interactioninhibitor-focused libraries to gain a better understanding of how these libraries were designed. The
most common were ligand- and structure-based approaches, along with various filtering steps, using
molecular descriptors. Often, these methods were combined to obtain the final library. We recognized
the abundance of targeted libraries offered and complimented by the inclusion of analytical data;
however, serious concerns had to be raised. Namely, vendors lack the information on the library
design and the references to the primary literature. Few references to active compounds were also
provided when using the ligand-based design and usually only protein classes or a general panel
of targets were listed, along with a general reference to the methods, such as molecular docking for
the structure-based design. No receptor data, docking protocols or even references to the applied
molecular docking software (or other HTVS software), and no pharmacophore or filter design
details were given. No detailed functional group or chemical space analyses were reported, and no
specific orientation of the libraries toward the design of covalent or noncovalent inhibitors could
be observed. All libraries contained pan-assay interference compounds (PAINS), rapid elimination
of swill compounds (REOS) and aggregators, as well as focused on the drug-like model, with the
majority of compounds possessing their molecular mass around 500 g/mol. These facts do not bode
well for the use of the reviewed libraries in drug design and lend themselves to commercial drug
companies to focus on and improve. Keywords: targeted libraries, focused libraries, computer-aided drug design, virtual screening, in silico drug design, high-throughput virtual screening Published in DKUM: 09.04.2025; Views: 0; Downloads: 3
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9. Parkinson’s disease non-motor subtypes classification in a group of Slovenian patients : actuarial vs. data-driven approachTimotej Petrijan, Jan Zmazek, Marija Menih, 2023, original scientific article Abstract: Background and purpose: The aim of this study was to examine the risk factors, prodromal symptoms, non-motor symptoms (NMS), and motor symptoms (MS) in different Parkinson’s disease (PD) non-motor subtypes, classified using newly established criteria and a data-driven approach.
Methods: A total of 168 patients with idiopathic PD underwent comprehensive NMS and MS examinations. NMS were assessed by the Non-Motor Symptom Scale (NMSS), Montreal Cognitive Assessment (MoCA), Hamilton Depression Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A), REM Sleep Behavior Disorder Screening Questionnaire (RBDSQ), Epworth Sleepiness Scale (ESS), Starkstein Apathy Scale (SAS) and Fatigue Severity Scale (FSS). Motor subtypes were classified based on Stebbins’ method. Patients were classified into groups of three NMS subtypes (cortical, limbic, and brainstem) based on the newly designed inclusion criteria. Further, data-driven clustering was performed as an alternative, statistical learning-based classification approach. The two classification approaches were compared for consistency.
Results: We identified 38 (22.6%) patients with the cortical subtype, 48 (28.6%) with the limbic, and 82 (48.8%) patients with the brainstem NMS PD subtype. Using a data-driven approach, we identified five different clusters. Three corresponded to the cortical, limbic, and brainstem subtypes, while the two additional clusters may have represented patients with early and advanced PD. Pearson chi-square test of independence revealed that a priori classification and cluster membership were significantly related to one another with a large effect size (χ2(8) = 175.001, p < 0.001, Cramer’s V = 0.722). The demographic and clinical profiles differed between NMS subtypes and clusters.
Conclusion: Using the actuarial and clustering approach, marked differences between individual NMS subtypes were found. The newly established criteria have potential as a simplified tool for future clinical research of NMS subtypes of Parkinson’s disease. Keywords: Parkinson’s disease, non-motor symptoms subtypes, a priori classification, cluster analysis Published in DKUM: 07.04.2025; Views: 0; Downloads: 2
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10. Periodic arrays of chiral domains generated from the self-assembly of micropatterned achiral lyotropic chromonic liquid crystalGeonhyeong Park, Simon Čopar, Ahram Suh, Minyong Yang, Uroš Tkalec, Dong Ki Yoon, 2020, original scientific article Abstract: Achiral building blocks forming achiral structures is a common occurrence in nature, while chirality emerging spontaneously from an achiral system is usually associated with important scientific phenomena. We report on the spontaneous chiral symmetry-breaking phenomena upon the topographic confinement of achiral lyotropic chromonic liquid crystals in periodically arranged micrometer scale air pillars. The anisotropic fluid arranges into chiral domains that depend on the arrangement and spacing of the pillars. We characterize the resulting domains by polarized optical microscopy, support their reconstruction by numerical calculations, and extend the findings with experiments, which include chiral dopants. Well-controlled and addressed chiral structures will be useful in potential applications like programmable scaffolds for living liquid crystals and as sensors for detecting chirality at the molecular level. Keywords: physical chemistry, atmospheric chemistry, chromatography, deformation, silicon, symmetry breaking, chiral domains, liquid crystal Published in DKUM: 03.04.2025; Views: 0; Downloads: 1
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