69 research outputs found

    Assessing environmental requirements effects on forest fragmentation sensitivity in two arboreal rodents

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    The study of the effect of habitat fragmentation on species that inhabit residual patches requires the investigation of the relationship existing between species distribution and landscape components. To understand which components of landscape mosaics are more influential for species’ persistence, we compared the distribution of two arboreal rodents proved to be sensitive to habitat fragmentation, the hazel dormouse Muscardinus avellanarius and the red squirrel Sciurus vulgaris. Their occurrence in residual oak woods in central Italy was studied with nest-boxes and hair-tubes, developing a new method for hair analysis. Their distributions were analysed considering patch, matrix composition and configuration, and landscape vegetation variables. The two species showed a different degree of plasticity, with the squirrel being significantly more specialised at the landscape scale. The comparison of the two distribution patterns highlighted the influence of different ecological constraints and the existence of different strategies to cope with fragmentation. Patch size and patch attributes were generally weaker determinants of occurrence, compared to landscape metrics. The squirrel presence was significantly influenced by the presence of shared perimeter between hedgerows and woods and by the lack of isolation of the residual patches, suggesting the use of several fragments to compensate the low habitat quality. Conversely the hazel dormouse seemed to be more affected by the internal management of the woods, and in particular by the mean DBH. Our results highlight how the recognition of the extrinsic constraints and the influence of multi-scale habitat selection may help guiding land use management, to ensure species conservation in profoundly exploited landscapes

    The Beta Ansatz: A Tale of Two Complex Structures

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    Brane tilings, sometimes called dimer models, are a class of bipartite graphs on a torus which encode the gauge theory data of four-dimensional SCFTs dual to D3-branes probing toric Calabi-Yau threefolds. An efficient way of encoding this information exploits the theory of dessin d’enfants, expressing the structure in terms of a permutation triple, which is in turn related to a Belyi pair, namely a holomorphic map from a torus to a P1 with three marked points. The procedure of a-maximization, in the context of isoradial embeddings of the dimer, also associates a complex structure to the torus, determined by the R-charges in the SCFT, which can be compared with the Belyi complex structure. Algorithms for the explicit construction of the Belyi pairs are described in detail. In the case of orbifolds, these algorithms are related to the construction of covers of elliptic curves, which exploits the properties of Weierstraß elliptic functions. We present a counter example to a previous conjecture identifying the complex structure of the Belyi curve to the complex structure associated with R-charges

    Assessing the distribution of exotic egg parasitoids of Halyomorpha halys in Europe with a large-scale monitoring program

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    The brown marmorated stink bug Halyomorpha halys is an invasive agricultural pest with a worldwide distribution. Classical biological control has been identified as the most promising method to reduce the populations of H. halys. Adventive populations of two candidates for releases, Trissolcus japonicus and Trissolcus mitsukurii, have recently been detected in Europe. To assess their distribution and abundance, a large-scale survey was performed. From May to September 2019, a wide area covering northern Italy and parts of Switzerland was surveyed, highlighting the expanding distribution of both Tr. japonicus and Tr. mitsukurii. Within four years after their first detection in Europe, both species have rapidly spread into all types of habitats where H. halys is present, showing a wide distribution and continuous expansion. Both exotic Trissolcus showed high levels of parasitism rate towards H. halys, while parasitization of non-target species was a rare event. The generalist Anastatus bifasciatus was the predominant native parasitoid of H. halys, while the emergence of native scelionids from H. halys eggs was rarely observed. The presence of the hyperparasitoid Acroclisoides sinicus was also recorded. This study provided fundamental data that supported the development of the first inoculative release program of Tr. japonicus in Europe

    Where are we now with European forest multi-taxon biodiversity and where can we head to?

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    The European biodiversity and forest strategies rely on forest sustainable management (SFM) to conserve forest biodiversity. However, current sustainability assessments hardly account for direct biodiversity indicators. We focused on forest multi-taxon biodiversity to: i) gather and map the existing information; ii) identify knowledge and research gaps; iii) discuss its research potential. We established a research network to fit data on species, standing trees, lying deadwood and sampling unit description from 34 local datasets across 3591 sampling units. A total of 8724 species were represented, with the share of common and rare species varying across taxonomic classes: some included many species with several rare ones (e.g., Insecta); others (e.g., Bryopsida) were represented by few common species. Tree-related structural attributes were sampled in a subset of sampling units (2889; 2356; 2309 and 1388 respectively for diameter, height, deadwood and microhabitats). Overall, multi-taxon studies are biased towards mature forests and may underrepresent the species related to other developmental phases. European forest compositional categories were all represented, but beech forests were over-represented as compared to thermophilous and boreal forests. Most sampling units (94%) were referred to a habitat type of conservation concern. Existing information may support European conservation and SFM strategies in: (i) methodological harmonization and coordinated monitoring; (ii) definition and testing of SFM indicators and thresholds; (iii) data-driven assessment of the effects of environmental and management drivers on multi-taxon forest biological and functional diversity, (iv) multi-scale forest monitoring integrating in-situ and remotely sensed information

    Futurismo, cultura e politica

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    Nell’ambito della mostra “Futurismo e Futurismi”, curata da Palazzo Grassi a Venezia nel 1986, la Fondazione Giovanni Agnelli organizzò a Venezia, il 15 e 16 maggio 1986, il convegno “Futurismo, Cultura e Politica”, volto ad esplorare la dimensione politica e meta-politica del movimento e della cultura futurista, in Italia ed all’estero. Il volume raccoglie i saggi nati dalle relazioni presentate in quella occasione.- Indice #5- Introduzione di Renzo De Felice #9- Parte Prima. Gli aspetti generali del rapporto tra futurismo, cultura e politica #13- Futurismo e culture politiche in Europa: una prospettiva globale, George L. Mosse #15- Il ruolo di Marinetti nella costruzione del futurismo, Luciano De Maria #35- Il futurismo nel dibattito intellettuale italiano dalle origini al 1920, Alberto Asor Rosa #51- Futurismo e sinistra politica, Umberto Carpi #69- Macchine e rarimerletti. Alcune fonti del futurismo nell’ideologia e nella letteratura, Roberto Tessari #81- Parte Seconda. L’esperienza politica del futurismo italiano #105- II futurismo e la politica. Dal nazionalismo modernista al fascismo (1909-1920), Emilio Gentile #107- Futurismo e fascismo, Niccolò Zapponi #163- Settimelli e Carli dal futurismo al fascismo, Paolo Buchignani #179- Bottai: da intellettuale futurista a leader fascista, Giordano Bruno Guerri #223- La politica culturale del fascismo, le avanguardie e il problema del futurismo, Enrico Crispolti #249- Parte Terza. Futurismo, cultura e politica fuori d’Italia #287- Futurismo e culture politiche in Francia, Pasquale A. Jannini #289- Futurismo e rivoluzione conservatrice in Germania, Ferruccio Masini #307- Il futurismo italiano e l’avanguardia ungherese, Gianpiero Cavaglià #323- I contatti politico-culturali tra futuristi italiani e Russia, Cesare G. De Michelis #355- Il secondo futurismo russo: la dimensione politica, Halina Stephan #385- Futurismo, ultraismo e culture politiche nell’area ispanica, Jaime Brihuega #411- Futurismo, vorticismo e “mondomoderno”, William C. Wees #443- Interventi #459- Arti liberali e diritto dell’individuo in F. T. Marinetti, Leonardo Clerici #461- Futurismo e dibattito politico, Emilio R. Papa #483- Spettacolo politico e “18 BL”, Marco Verdone #48
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