1,721,014 research outputs found
Geometry, Topology and Simplicial Synchronization
Full text link32 pages, 10 figures32 pages, 10 figures32 pages, 10 figures32 pages, 10 figuresSimplicial synchronization reveals the role that topology and geometry have in determining the dynamical properties of simplicial complexes. Simplicial network geometry and topology are naturally encoded in the spectral properties of the graph Laplacian and of the higher-order Laplacians of simplicial complexes. Here we show how the geometry of simplicial complexes induces spectral dimensions of the simplicial complex Laplacians that are responsible for changing the phase diagram of the Kuramoto model. In particular, simplicial complexes displaying a non-trivial simplicial network geometry cannot sustain a synchronized state in the infinite network limit if their spectral dimension is smaller or equal to four. This theoretical result is here verified on the Network Geometry with Flavor simplicial complex generative model displaying emergent hyperbolic geometry. On its turn simplicial topology is shown to determine the dynamical properties of the higher-order Kuramoto model. The higher-orderKuramoto model describes synchronization of topological signals, i.e. phases not only associated to the nodes of a simplicial complexes but associated also to higher-order simplices, including links, triangles and so on. This model displays discontinuous synchronization transitions when topological signals of different dimension and/or their solenoidal and irrotational projections are coupled in an adaptive way
Pesci e acque interne del Friuli Venezia Giulia. Aggiornamento parziale della Carta Ittica (1992)
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Detecting informative higher-order interactions in statistically validated hypergraphs
Full text linkRecent empirical evidence has shown that in many real-world systems, successfully represented as networks, interactions are not limited to dyads, but often involve three or more agents at a time. These data are better described by hypergraphs, where hyperlinks encode higher-order interactions among a group of nodes. In spite of the extensive literature on networks, detecting informative hyperlinks in real world hypergraphs is still an open problem. Here we propose an analytic approach to filter hypergraphs by identifying those hyperlinks that are over-expressed with respect to a random null hypothesis, and represent the most relevant higher-order connections. We apply our method to a class of synthetic benchmarks and to several datasets, showing that the method highlights hyperlinks that are more informative than those extracted with pairwise approaches. Our method provides a first way, to the best of our knowledge, to obtain statistically validated hypergraphs, separating informative connections from noisy ones
Osservazioni sulla biometria di Cyprinus carpio Linnaeus, 1758 nella bassa pianura del Friuli Venezia Giulia (Osteichthyes, Cyprinidae)
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Elites, communities and the limited benefits of mentorship in electronic music
Full text linkWhile the emergence of success in creative professions, such as music, has been studied extensively, the link between individual success and collaboration is not yet fully uncovered. Here we aim to fill this gap by analyzing longitudinal data on the co-releasing and mentoring patterns of popular electronic music artists appearing in the annual Top 100 ranking of DJ Magazine. We find that while this ranking list of popularity publishes 100 names, only the top 20 is stable over time, showcasing a lock-in effect on the electronic music elite. Based on the temporal co-release network of top musicians, we extract a diverse community structure characterizing the electronic music industry. These groups of artists are temporally segregated, sequentially formed around leading musicians, and represent changes in musical genres. We show that a major driving force behind the formation of music communities is mentorship: around half of musicians entering the top 100 have been mentored by current leading figures before they entered the list. We also find that mentees are unlikely to break into the top 20, yet have much higher expected best ranks than those who were not mentored. This implies that mentorship helps rising talents, but becoming an all-time star requires more. Our results provide insights into the intertwined roles of success and collaboration in electronic music, highlighting the mechanisms shaping the formation and landscape of artistic elites in electronic music
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Distribuzione ed abbondanza dei macroinvertebrati bentonici in un tratto del Rio Bianco (Tarvisio, Alpi Giulie)
No full textIn questo lavoro viene descritta la distribuzione e l’abbondanza dei macroinvertebrati bentonici in un tratto del Rio Bianco (Bacino del Torrente Slizza). Il tratto analizzato si trova nei pressi di San Antonio Oltreacqua (Tarvisio). All’interno del tratto sono stati analizzati quattro punti, caratterizzati da differente morfologia degli habitat acquatici (rapide, buche). Campioni quantitativi di macroinvertebrati bentonici sono stati raccolti stagionalmente, fra il luglio 2003 e il maggio 2004.
Gli organismi raccolti sono prevalentemente Insetti, appartenenti agli orsini Plecoptera, Ephemeroptera, Trichoptera e Diptera. Lo studio della comunità macrozoobentonica, nelle diverse stagioni, ha consentito di stabilire che, le variazioni della composizione e biomassa totale della comunità, sono simili nei punti a corrente veloce, mentre differiscono nell’unico punto dove la corrente è lenta. Questo suggerisce l’importanza della scelta dei tratti assunti come rappresentativi per studi di carattere ecologico. La complessità morfologica dei torrenti alpini sembra determinare la distribuzione e l’abbondanza dei macroinvertebrati bentonici e dovrebbe esser presa in considerazione nella stima della biomassa media di un tratto torrentizio montano
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