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Duality theorems and Kolyvagin systems for elliptic curves
Get PDFAfter developing the theory of arithmetic duality for Galois cohomology
with a particular focus on the cohomology of an elliptic curve over a local
field or a number field, we use these results to define Kolyvagin systems
and show how they provide bounds for the Selmer groups of the elliptic
curve
From the Pell's equation to Gross-Stark units
Get PDFThis thesis is a mathematical journey from the Pell’s equation to Gross–Stark units, centered around the theme of the relationship between leading terms of L-series, and algebraic units. Our story begins with Pell’s equation, and two methods to solve it. In particular, we will focus on the study the fundamental solution of a real quadratic number field k. Then we will move to a general abelian extension of number fields K/k by stating the Stark conjecture. To conclude we will discuss the p-adic analogue of the Stark conjecture, namely the Gross–Stark conjecture. We will state the conjecture for k a real quadratic number field and K its narrow Hilbert class field. We will define the Gross–Stark unit, and compute an explicit exampl
Bootstrap multi-curva: analisi delle caratteristiche principali ed implementazione.
No full textMetodologie per le operazioni di bootstrap della curva di rendimento,
analisi dei principali strumenti finanziari utilizzati e risultati concreti
dell'implementazioni di un algoritmo di bootstrap
Caratterizzazione petrografica delle litologie oceaniche associate alle mineralizzazioni a solfuri massivi nella Zona Piemontese del Colle della Borra (Val Soana, Alpi Occidentali)
Get PDFThe study area is located at Colle della Borra (2.578 m), within the Piemonte Zone, where new detailed observations on the geological context and on lithologies associated with massive sulphide mineralization were made. The meta-ophiolite exposed at Colle della Borra, consisting of abundant calcschists and micaschists with metabasites, quartz-ites, marbles, chloriteschists and metasomatic metagabbros, have long been considered to be of Combin type, belonging to the greenschist-facies Colle della Rosa-Dondena tectonic Unit (CRD), interposed between two eclogitic-facies ophiolitic units.
In this work, garnet-chloritoid-, garnet-titanite-bearing phengitic leaden micas-chists and lawsonite-bearing calcschists preserving an old schistosity, have been investi-gated in detail. The high-pressure tectono-metamorphic evolution of meta-ophiolites in the study area has been qualitatively constrained based on the comparison with analogous parageneses in Grt-Cld-bearing micaschists along the Western Alps. This comparison suggests the presence of relict eclogitic-facies metamorphic imprint in this area. Three main metamorphic stages have been recognized: 1) D1 phase which developed during prograde path of the Alpine subduction producing the S1 foliation (S1 relict foliation is documented by the occurrence of rootless isoclinal folds); 2) the D2 phase which started at the metamorphic HP peak producing the S2 foliation and then developed during exhu-mation under blueschist‐ to greenschist-facies conditions (S2 pervasive plane-parallel fo-liation is marked by eclogite‐facies mineral assemblages partly retrogressed; 3) D3 (with-out foliation) which represents the late stage that locally developed an incipient crenula-tion cleavage; all the D2 structures were overprinted by D3 larger folds.
Considering the abundant relicts of lawsonite completely replaced by zoisite + phengite (partly recrystallized into Fe-epidote and paragonite) in the calcschists, an origin from fluid‐rock interaction and Ca‐metasomatism in the subduction environment is in-ferred for this lithology. The presence of lawsonite relicts is a clear evidence of the intense process of Ca-metasomatism along the subduction channel during prograde evolution. The lawsonite breakdown is testified by Ca-rich garnet rims in the micaschists.
The ophiolitic sequence shows both a continental affinity (calcschists and micas-chists) and an oceanic affinity (presence of VMS mineralisation and metabasites) and can be interpreted to reflect an original ocean-continent-transition (OCT) zone. The sequence probably derived from a slow-ultraslow-spreading-ridge segment affected by hydrother-mal fluid circulation (testified by presence of VMS deposit) and by intense tectonic ac-tivity, near a continental margin.
The presence of high-pressure mineral assemblages in the meta-ophiolites of the Colle della Borra sequence suggests they do not represent a greenschist-facies CRD slice, but rather the top portion of the eclogite metasedimentary cover of the Zermatt-Saas oph-iolites, which are exposed about 150 meters downstream towards Campiglia. Conse-quently, the sequence of Colle della Borra calls for reconsidering the tectono-metamor-phic evolution of the entire CRD and of all ophiolitic units described in the Upper Soana valley (Piamprato and Campiglia valleys). This study marks the starting point for further studies in this area, which could help to overcome the limits imposed by mineralogical associations. A modern approach to the study of ophiolites in this area has to combine the geological data with both the deformation distribution, the paleogeographic reconstruc-tion and the metasomatic processes that occurred during subduction
Ruolo prognostico di Red blood cell Distribution Width (RDW) in cani con malattia degenerativa della valvola mitralica
Get PDFStakeholder management, corporate governance e performance economico-finanziarie: evidenze empiriche nel settore luxury
Get PDFEvergreening in pharmaceuticals: "gaming" the patent system? The ongoing backlash between the Indian and US patent law.
Get PDFStudy of the Hα emission of the SPIDER negative ions source
Get PDFThis dissertation assesses and compares plasma behaviour under different configurations of the plasma grid magnetic filter in the SPIDER experiment, part of the larger ITER project, through the study of the Hα emission of the hydrogen plasma.
ITER is an international collaboration, involving the European Union, China, India, Japan, Korea, Russia and the United States, whose objective is to demonstrate the feasibility of fusion power generation through plasma magnetic confinement. A low density hydrogen plasma will be heated to about 1.5 · 108 K to start the nuclear fusion reaction. The project design will allow a self-sustaining process for long-duration machine runs (up to 1 h) to reach the 500 MW of fusion power output goal [1]. Many systems and subsystems are needed to reach such a high temperature: together with ohmic heating, thermal energy will be fed to the plasma via microwave radiation and neutral particle scattering, provided by two neutral beam injectors (NBI).
The SPIDER ion source is part of the NBI system, providing up to 60 A current of H− ions extracted from a hydrogen plasma. Ions are then accelerated up to 100 keV and neutralised to obtain a high intensity neutral beam [2]. However, to achieve the required specification to ignite nuclear fusion and obtain the best power out- put, all systems need to achieve maximum optimisation.
In the specific case of SPIDER, efficiency is achieved by maximising the spatial homogeneity of the neutral beam, which, in-turn, depends on the uniformity of the plasma produced in the source, which is required to deviate less than ±10% from ideal uniformity [2]. Many of SPIDER source components are still being tuned to solve stability and homogeneity issues, as well to increase the negative ions production. Thus, the study of the effects of the PG magnetic field topology on the produced plasma is of great interest to obtain the required data to improve plasma uniformity.
In this dissertation, the SPIDER plasma source is introduced, along with the components of interest of this study, namely the plasma grid magnetic filter, in two topological configurations: a first prototype and a second improved one, and the plasma generators. Data analysis is then outlined presenting labelling, analysis roadmap and methodology. Finally, results assessment and description is conducted to lead to the final data comparison across different analysis methods
Borrelia spp. e tick-borne encephalitis virus in zecche prelevate da uccelli migratori in Nord-Est Italia
No full textIl presente progetto di tesi tratta il ruolo degli uccelli migratori nella diffusione delle zecche e nella disseminazione dei patogeni ad esse associati, nel Nord-Est Italia. In questa zona infatti, ed in particolare in Friuli Venezia Giulia, le malattie zoonosiche trasmesse da zecche hanno assunto importanza crescente, dal momento che si riscontrano frequentemente casi di malattia dovuta a TBDs nell’uomo. Si è deciso di indagare due agenti infettivi trasmessi da zecche, ovvero Borrelia spp. e tick-borne encephalitis virus, responsabili rispettivamente della malattia di Lyme e dell’encefalite virale da zecche, che sono entrambe malattie endemiche in Friuli Venezia Giulia. L’obiettivo era quello di capire se, e in che termini, gli uccelli migratori possano effettivamente contribuire all’epidemiologia di questi due patogeni.
Le zecche sono state prelevate dalle specie avicole migratorie durante le procedure di inanellamento svolte nella stazione Malga Confin, situata nelle Prealpi Giulie, tra settembre e novembre del 2019 e del 2020; questo periodo corrisponde al passaggio autunnale degli uccelli migratori intrapaleartici che seguono la rotta europea Nord-Est Sud-Ovest, in direzione Sud-Ovest. Le zecche sono state poi identificate morfologicamente allo stereomicroscopio e microscopio. La ricerca di Borrelia spp. e TBEV è stata realizzata con metodiche biomolecolari di real-time PCR e PCR.
Durante l’inanellamento di 3414 esemplari totali, sono state prelevate ed in un secondo momento analizzate 209 zecche albergate da 88 uccelli, appartenenti a 8 specie migratorie diverse; tutte le zecche appartenevano alla specie I. ricinus, eccetto una I. frontalis prelevata da un pettirosso (Erithacus rubecula) e una I. acuminatus prelevata da un tordo sassello (Turdus iliacus).
I risultati hanno evidenziato come gli uccelli migratori siano generalmente poco infestati dalle zecche (2,58%), ma quasi la metà di esse (48,8%) siano positive a Borrelia spp. Gli uccelli del genere Turdus (Turdus merula, Turdus iliacus e Turdus philomelos) sono risultati i più infestati e quelli che albergano la maggior parte delle zecche positive. Il sequenziamento di Borrelia spp. ha identificato 4 genospecie: la più prevalente è B. garinii, specie neurotropa classificata dall’ECDC come una delle principali responsabili di borreliosi di Lyme nell’uomo, seguita da B. valaisiana, B. afzelii e B. miyamotoi.
Non sono state invece evidenziate positività per il TBEV.
Il confronto di questi risultati con quelli riportati in letteratura ha permesso di sviluppare alcune considerazioni sul ruolo epidemiologico delle varie specie di uccelli migratori e sulla loro capacità di diffusione degli agenti infettivi indagati, sia a livello dell’area del campionamento, sia a livello più ampio, in relazione all’arco alpino e ai paesi europei attraversati dalla stessa rotta migratoria
