1,255 research outputs found
IL DILEMMA DEL DEGRADO DEL SUOLO INDOTTO DALLA PRESENZA DI STRADE (ROADSIDE)
No full textNegli ultimi decenni, la crescente antropizzazione che si è verificata su scala globale si è tradotta in un generale aumento nella pianificazione e costruzione di reti viarie, al fine di incrementare la produttività dei sistemi agricoli e forestali, favorire la circolazione delle merci e promuovere in generale lo sviluppo delle nostre società. Nonostante tali vantaggi, la presenza di reti stradali può essere particolarmente critica sia in termini idrologici che geomorfologici, alterando le naturali dinamiche dei processi idrologici delle aree in cui le reti viarie vengono costruite e favorendo allo stesso tempo l’attivazione di processi di degrado del suolo come fenomeni erosivi, frane e problemi di instabilità del terreno. A questo proposito, il progresso scientifico degli ultimi tempi si è tradotto nella possibilità di applicare software, strumenti e tecnologie grazie alle quali effettuare analisi topografiche ad alta risoluzione, ricostruzioni dettagliate del terreno e quindi realizzare dettagliate analisi idrologiche e geomorfologiche a scale spaziali differenti. Le tecniche fotogrammetriche (e.g. la tecnica Structure from Motion -SfM), combinate con l’utilizzo di droni (Uncrewed Aerial Vehicles-UAV) e tecnologie di telerilevamento (e.g. sistemi Light Detection and Ranging -LiDAR), hanno consentito di ottenere informazioni spaziali ad altissima risoluzione e a basso costo ripetute nel tempo. Alla luce di questi aspetti, questa tesi nasce con l'obiettivo di colmare specifiche lacune scientifiche relativamente il ruolo svolto dalle reti viarie nell’attivazione di processi di degrado del suolo quali per esempio frane superficiali e dinamiche erosive del terreno, specialmente in condizioni di forte pendenza. Questo lavoro si articola pertanto in quattro differenti ricerche, basate sulla raccolta di dati in campo e sulla conseguente applicazione di modelli matematici e Sistemi Informativi Geografici (GIS). Partendo quindi dal contesto agricolo e passando ai sistemi montani e forestali, la tesi propone diversi studi innovativi riguardo il dilemma del degrado del suolo indotto dalla presenza di strade, attraverso la redazione di quattro articoli scientifici proposti in diverse riviste internazionali. A questo proposito, vengono suggerite nuove metodologie potenzialmente applicabili in altri contesti e aree di studio differenti, al fine di supportare gli stakeholders e le comunità locali nell’attuare specifici interventi sul territorio in grado di mitigare e soprattutto prevenire il verificarsi di simili problematiche in futuro.In the last decades, the growing anthropization occurring worldwide translated into the increasing construction of roads and trails, useful for support agricultural and forested systems productivity, encourage goods movement and generally promote the development of our societies. At the same time, the presence of road networks frequently represents a critical issue in hydrological and geomorphological terms, critically interacting with natural hydrological dynamics and similarly promoting land degradation processes such as erosive phenomena, landslides and terrain instabilities. In this regard, the scientific progress led the possibility to apply softwares, tools and technologies able to perform high-resolution topographic analysis, detailed terrain reconstructions and therefore increasing the opportunity to compute hydrological and geomorphological analysis at local and wider scales. In this regard, photogrammetric techniques (e.g. Structure from Motion -SfM), combined with Uncrewed Aerial Vehicles (UAV) and Light Detection and Ranging (LiDAR)-based Airborne Laser Scanning (ALS) technology further allowed to obtain detailed spatial information for scientific purposes. This thesis arises in light of the above issues, aiming to overcame specific gaps in the scientific knowledge regarding the role of roads in the occurrence of land degradation processes such as shallow landslides and local erosive dynamics. This work is basically structured around four researches, based on data collection in the field, application of mathematical models and Geographic Information Systems (GIS). Starting from agricultural context and therefore moving to mountain and forested systems, the thesis proposes advances for science regarding the dilemma of roads-induced land degradation processes through four scientific articles. New methodologies are proposed in this regard, potentially applicable in other contexts and study areas in order to support stakeholders and local communities in promoting specific interventions and decisions able to mitigate and prevent the occurrence of similar issues in the future
The quantum 1/2 BPS Wilson loop in N= 4 Chern-Simons-matter theories
No full textIn three dimensional N= 4 Chern-Simons-matter theories two independent fermionic Wilson loop operators can be defined, which preserve half of the supersymmetry charges and are cohomologically equivalent at classical level. We compute their three-loop expectation value in a convenient color sector and prove that the degeneracy is uplifted by quantum corrections. We expand the matrix model prediction in the same regime and by comparison we conclude that the quantum 1/2 BPS Wilson loop is the average of the two operators. We provide an all-loop argument to support this claim at any order. As a by-product, we identify the localization result at three loops as a correction to the framing factor induced by matter interactions. Finally, we comment on the quantum properties of the non-1/2 BPS Wilson loop operator defined as the difference of the two fermionic ones.Fil: Bianchi, Marco S.. Queen Mary, University Of London; Reino UnidoFil: Griguolo, Luca. Università di Parma; ItaliaFil: Leoni Olivera, Matías. Universidad de Buenos Aires. Facultad de Ciencias Exactas. Departamento de Ecología, Genética y Evolución. Buenos Aires; ArgentinaFil: Mauri, Andrea. Universita Degli Studi Di Milano - Bicocca; ItaliaFil: Penati, Silvia. Universita Degli Studi Di Milano - Bicocca; Italia. Istituto Nazionale Di Fisica Nucleare, Frascati; ItaliaFil: Seminara, Domenico. Università degli Studi di Firenze; Itali
Hodge-to-singular correspondence for reduced curves
No full textWe study the summands of the decomposition theorem for the Hitchin system for GLn, in arbitrary degree, over the locus of reduced spectral curves. A key ingredient is a new correspon- dence between these summands and the topology of hypertoric quiver varieties. In contrast to the case of meromorphic Higgs fields, the intersection cohomology groups of moduli spaces of regular Higgs bundles depend on the degree. We describe this dependence.
n
, in arbitrary degree, over the locus of reduced spectral curves. A key ingredient is a new correspondence between these summands and the topology of hypertoric quiver varieties. In contrast to the case of meromorphic Higgs fields, the intersection cohomology groups of moduli spaces of regular Higgs bundles depend on the degree. We describe this dependence
Interventions, Productions and Collaborations:the relationship between RAI and visual artists
No full textOn the 17th May 1952, before RAI Radiotelevisione Italiana Studios began their regular broadcast from Milan, the Spatialist painter and sculptor Lucio Fontana broadcast his own experimental ‘artwork’ on Italian television, beginning a fruitful relationship between RAI and visual artists. For some, it provided careers as designers and art directors, such as the painter Mario Sasso and the Arte Povera artist Pino Pascali, while for others, who were given unique access to RAI’s television apparatus, it was an opportunity to explore their own artistic experimentations with an expensive and exclusive medium, such as Carlo Quartucci and Gianni Toti. RAI also hosted seminal artists’ performances on screen including John Cage and Fabio Mauri. This article, based on documents and interviews collected during the Arts and Humanities Research Council funded project REWINDItalia, discusses these and other seminal cases as well as tracing and assessing the history of this fruitful and complex exchange between RAI and visual artists
Qui sont les Dii mauri ?
No full textThe author reviews the various but rare interpretations of the divine collectivity referred to by the name of Dii Mauri. From a re-examination of the literary or epigraphic mentions of the 50 specifically African local or regional divinities, and of the 20 dedications to the Dii Mauri known to this day, he believes he can propose the relationship, even the identity, between the local gods and the Dii Mauri. The comparison between the authors of the dedications shows that the worship of the local gods principally concerned « civilians » (82,5 %), whereas the Dii Mauri were invoked by governors, imperial procurators, soldiers (81,25 %). Moreover the Dii Mauri are invoked as often in Numidia and in Africa as in Caesarian Mauretania (they are unknown in Tingitana). Therefore the term of "maurus" is not linked to the Roman administrative carving, it applies to what is rebellious to Latin culture, to what is specifically native and unassimilable. Dii Mauri and African gods are the same divinities, only the dedicators change.The author reviews the various but rare interpretations of the divine collectivity referred to by the name of Dii Mauri. From a re-examination of the literary or epigraphic mentions of the 50 specifically African local or regional divinities, and of the 20 dedications to the Dii Mauri known to this day, he believes he can propose the relationship, even the identity, between the local gods and the Dii Mauri. The comparison between the authors of the dedications shows that the worship of the local gods principally concerned « civilians » (82,5 %), whereas the Dii Mauri were invoked by governors, imperial procurators, soldiers (81,25 %). Moreover the Dii Mauri are invoked as often in Numidia and in Africa as in Caesarian Mauretania (they are unknown in Tingitana). Therefore the term of "maurus" is not linked to the Roman administrative carving, it applies to what is rebellious to Latin culture, to what is specifically native and unassimilable. Dii Mauri and African gods are the same divinities, only the dedicators change.Camps Gabriel. Qui sont les Dii mauri ?. In: Antiquités africaines, 26,1990. pp. 131-153
Diversity management e società multiculturale: teorie e prassi.
No full textIl libro illustra in una prospettiva internazionale i percorsi di empowerment lavorativo degli stranieri operanti in imprese multiculturali. Le prospettive di diversi paesi (USA, UK, Spagna, Belgio e Italia) sono confrontate alla ricerca di prassi comuni e diversità.
Nel rispetto dello spirito interculturale che anima il libro, i contributi sono conservati nelle lingue originarie degli autori (italiano, inglese, francese, spagnolo)
Cellular Automata Pseudo-Random Number Generators and Their Resistance to Asynchrony
No full textCellular Automata (CA) have a long history being employed as pseudo-random number generators (PRNG), especially for cryptographic applications such as keystream generation in stream ciphers. Initially starting from the study of rule 30 of elementary CA, multiple rules where the objects of investigation and were shown to be able to pass most of the rigorous statistical tests used to assess the quality of PRNG. In all cases, the CA employed where of the classical, synchronous kind. This assumes a global clock regulating all CA updates which can be a weakness if an attacker is able to tamper it. Here we study how much asynchrony is necessary to make a CA-based PRNG ineffective. We have found that elementary CA are subdivided into three class: (1) there is a “state transition” where, after a certain level of asynchrony, the CA loses the ability to generate strong random sequences, (2) the randomness of the sequences increases with a limited level of asynchrony, or (3) CA normally unable to be used as PRNG exhibit a much stronger ability to generate random sequences when asynchrony is introduced
Multi-temporal modeling of road-induced overland flow alterations in a terraced landscape characterized by shallow landslides
No full textThe presence of roads in high steep agricultural systems is often linked with landslides occurrence. This research aims to model multi-temporal overland flow dynamics in a shallow landslides-prone terraced landscape (northern Italy).The combined use of Remotely Piloted Aircraft Systems (RPAS) and photogrammetric techniques (e.g., Structure from Motion-SfM) allowed to elaborate multi-temporal high-resolution Digital Elevation Models (DEMs). Hydrological analyses of water flow’s depth alterations due to the road presence were carried out adopting the SIMulated Water Erosion model (SIMWE), focusing on different scenarios considering the presence of the road and assuming its absence through a specific DEM smoothing procedure. The possibility to perform multi-temporal hydrological simulations at a hillslope scale so as to analyse the role played by the road in overland flows alteration is still a challenge to be investigated. Results proved the role played by the road in water flows change above the two observed shallow landslides, with respective maximum water depth values equal to 0.18 m and 0.14 m. On the contrary, no-road simulations not revealed significant water flows deviations towards landslides, with water depth values around 0 m, underlining that the absence of the road would avoid relevant changes in water flow paths toward the collapsed surfaces. This work could be a solid starting point for analyse road impact on runoff dynamics and hillslopes stability also at a wider scale, as well as for planning efficient mitigation intervention so as to reduce the occurrence of similar future scenarios
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