346 research outputs found

    ENVIRONMENTAL SUSTAINABILITY INDICATORS IMPLEMENTED IN A DECISION SUPPORT SYSTEM FOR VITICULTURAL SECTOR

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    La tesi si basa sui principi della sostenibilità ambientale applicati al settore della viticultura. I principali obiettivi sono: i) analisi della letteratura riguardante gli indicatori agro-ambientali, ii) sviluppo di una metodologia innovativa per valutare l’impatto ambientale della viticultura e, iii) applicazione della metodologia in casi pratici. La parte introduttiva è dedicata all’analisi degli indicatori agro-ambientali e delle relative politiche europee, alle tematiche inerenti il vino sostenibile e i sistemi di supporto alle decisioni per una viticultura sostenibile. Nella seconda parte è presentata una rigorosa e completa metodologia per valutare il livello di sostenibilità in tutte le fasi della produzione di uva, usando sia indicatori agronomici sia l’approccio della valutazione del ciclo di vita (Life Cycle Assessment). Sono state identificate sei categorie di impatto: salute umana, aria, suolo, biodiversità, consumi energetici e uso dell’acqua. Ogni categoria è composta da sotto-indicatori, per un totale di 21 sotto-indicatori, ognuno dei quali avente un punteggio (da 0 a 5) e un peso relativo nel punteggio complessivo di sostenibilità (da 0 a 5). La terza parte riguarda l’applicazione della metodologia in casi studio all’interno del progetto europeo “InnoVine”. Il lavoro di ricerca è stato realizzato seguendo le linee guida di standard internazionali e documentate fonti di letteratura per la valutazione della prestazione ambientale ed elaborando metodologie originali per la raccolta dei dati, la quantificazione degli impatti e l’interpretazione dei risultati. Infine, i risultati ottenuti confermano: i) la validità della metodologia nel calcolare gli impatti delle differenti pratiche viticole sull’ambiente e, ii) la possibilità di implementare la metodologia in un sistema di supporto alle decisioni per una viticultura sostenibile.The thesis focuses on environmental sustainability principles applied to the viticultural sector. The main goals are: (i) analysis of the literature background on agri-environmental indicators, (ii) development of an innovative methodology to assess environmental impacts of viticulture, and (iii) testing of the methodology in practical cases. The introduction is dedicated to the analysis of the agri-environmental indicators and the related EU policies, sustainable wine issues, and decision support systems for a sustainable viticulture. In the second part, a rigorous and complete methodology is developed to assess the sustainability level of viticulture in all the phases of the grape growing using both agronomic indicators and the Life Cycle Assessment approach. Six impact categories were identified: human health, air, soil, biodiversity conservation, energetic consumptions, and water use. Each category is composed by sub-indicators, for a total of 21 sub-indicators, each of them having a score (between 0 and 5) and a defined weight on the overall sustainability score (between 0 and 5). In the third part, the methodology was tested in practical cases within the European project “InnoVine”. The study is carried out following the guidelines from international standards and from documented literature sources for the assessment of the environmental performance and elaborating original methodologies for the input data collection, the quantification of the impacts, and the interpretation of the results. Finally, the results obtained confirm: i) the methodology validity in quantifying the impacts of different grape production practices on the environment, and ii) the possibility to implement the methodology in a decision support system for a sustainable viticulture

    Radio morphology-accretion mode link in FRII low-excitation radio galaxies

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    Questo lavoro di tesi consiste nello studio sistematico di una popolazione di radiogalassie con comportamenti apparentemente difformi tra banda radio e ottica. Si tratta di AGN radio-loud molto potenti, con emissione radio estesa tipica di radiogalassie. Gli oggetti analizzati in questo lavoro sono classificati in banda radio come FRII, essendo caratterizzate su larga scala dalla presenza di hot-spot e assenza di getti gemelli. Sono invece classificate come LERG (Low Excitation Galaxies) in banda ottica, per via della presenza di alcune righe di emissione che permettono di stabilire il grado di eccitazione delle regioni centrali. Il catalogo da cui queste sono estratte è il 3CR, imponendo un taglio in redshift per z<0.3. Per quanto riguarda i dati ottici, radio e la classificazione di tutte le sorgenti, si è fatto riferimento agli articoli di Buttiglione et al. (2009). L'analisi in banda X è stata svolta utilizzando i dati di archivio pubblici dei telescopi Chandra e XMM-Newton. Una volta estratto lo spettro di emissione, per ogni sorgente si è cercato di ricostruire e studiare il modello fisico che meglio ne descrivesse l'emissione. La raccolta e unione di dati radio, ottici e X per un campione completo di FRII-LERGs costituisce un punto nodale per la comprensione complessiva delle proprietà ambientali, di emissione ed accrescimento delle radio galassie. Lo studio dei meccanismi che portano alla formazione di questa popolazione è infatti, allo stato attuale, lontano da una comprensione completa e univoca. Una volta unite le informazioni provenienti dalle varie bande è stato possibile raggiungere una visione d'insieme e trarre alcune conclusioni. Per alcune proprietà intrinseche questa popolazione di radiogalassie si trova a metà strada tra FRII-HERGs e FRI-LERGs, permettendo di avvalorare l'ipotesi secondo cui la popolazione delle FRII-LERGs stia sperimentando una fase di transizione

    Optimiser l’activité d’une école de sports de neige en attirant une clientèle locale en périodes de basse saison: l’exemple de l’École Suisse de Ski de Montana

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    L’objectif de ce travail est de trouver des solutions pour faire face aux creux de saison hivernale dans le cadre d’une école de ski, en attirant une clientèle locale. Dans ce travail, le cas de l’École Suisse de Ski (ESS) de Montana a été étudié. Une analyse du comportement des Suisses aux sports d’hiver a permis de comprendre qu’une école de ski doit savoir motiver les jeunes pour assurer sa pérennité, en rendant son image plus fun que studieuse. Une analyse de la demande, effectuée dans le cadre de ce travail auprès d’une population de proximité a mis en évidence que le facteur le plus important pour rendre une école de ski attractive n’est pas seulement le prix, mais aussi la différentiation de l’offre. De plus, cette étude démontre que la population locale profite majoritairement de son domaine skiable durant les périodes de faible affluence et qu’elle représente donc une clientèle potentielle pour ces périodes creuses. Grâce à des entretiens qualitatifs avec des leaders d’opinion et l’envoi d’un questionnaire, une comparaison nationale et internationale a prouvé qu’une école peut améliorer sa fréquentation à ces périodes en proposant des offres pour les écoliers de la région d’une station de ski. Cependant, cette comparaison démontre également qu’une ESS ne peut pas résoudre le problème de basse saison en attirant seulement une population locale. D’autres pistes restent donc à explorer. Enfin, des produits destinés aux enfants et aux seniors locaux sont proposés pour fournir à l’ESS Montana des solutions concrètes à mettre en place

    STRSCNE

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    Partially Updated Switching-Method for systems of nonlinear equations

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    AbstractA hybrid method for solving systems of n nonlinear equations is given. The method does not use derivative information and is especially attractive when good starting points are not available and the given system is expensive to evaluate. It is shown that, after a few steps, each iteration requires (2k + 1) function evaluations where k, 1 â©˝ k â©˝ n, is chosen so as to have an efficient algorithm. Global convergence results are given and superlinear convergence is established. Some numerical results show the numerical performance of the proposed method

    Processi di scattering in astrofisica

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    L'attenzione è stata posta su tre fenomeni fondamentali di scattering: Thomson, Compton e Compton inverso. Sono state sottolineate alcune ed eventuali applicazioni astrofisiche di questi e valutate le implicazioni o generalizzazioni che da tali fenomeni possono derivare: Synchrotron Self-Compton, Comptonizzazione ed effetto Sunyaev-Zeldovich termico. Infine è stato preso un caso astrofisico come applicazione di questi fenomeni: Sagittarius A*, una fonte radio proveniente dal centro della nostra galassia, molto studiata negli anni, citando un articolo pubblicato su una rivista scientifica nel 2012

    Cross-population radio galaxies as a test of the jet-accretion relationship

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    Radio galaxies (RGs) are extremely relevant in addressing important unknowns concerning the interaction among black hole accretion, radio jets, and the environment. In the classical scheme, their accretion rate and ejection of relativistic jets are directly linked: efficient accretion (HERG) is associated with powerful edge-brightened jets (FRIIs); inefficient accretion (LERG) is associated with weak edge-darkened jets (FRIs). The observation of RGs with an inefficient engine associated with edge-brightened radio emission (FRII-LERGs) broke this scheme. FRII-LERGs constitute a suitable population to explore how accretion and ejection are linked and evaluate the environment's role in shaping jets. To this aim, we performed a multiwavelength study of different RGs catalogs spanning from Jy to mJy flux densities. At first, we investigated the X-ray properties of a sample of 51 FRIIs belonging to the 3CR catalog at z<0.3. Two hypotheses were invoked to explain FRII-LERGs behavior: evolution from classical FRIIs; the role of the environment. Next, we explored the mJy sky by studying the optical-radio properties of hundreds of RGs at z<0.15 (Best & Heckman 2012 sample). FRII-LERGs appear more similar to the old FRI-LERGs than to the young FRII-HERGs. These results point towards an evolutive scenario, however, nuclear time scale changes, star population aging, and kpc-Mpc radio structure modification do not agree. The role of the Mpc environment was then investigated. The Wen et al. 2015 galaxy clusters sample, built exploiting the SDSS survey, allowed us to explore the habitat of 7219 RGs at z<0.3. Most RGs are found to live in outside clusters. For these sources, differences among RG classes are still present. Thus, the environment is not the key parameter, and the possibility of intrinsic differences was reconsidered: we speculated that different black hole properties (spin and magnetic field at its horizon) could determine the observed spread in jet luminosity

    MicroRNA-184 is a downstream effector of albuminuria driving renal fibrosis in rats with diabetic nephropathy

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    Renal fibrosis is a common complication of diabetic nephropathy and is a major cause of end-stage renal disease. Despite the suggested link between renal fibrosis and microRNA (miRNA) dysregulation in diabetic nephropathy, the identification of the specific miRNAs involved is still incomplete. The aim of this study was to investigate miRNA profiles in the diabetic kidney and to identify potential downstream targets implicated in renal fibrosis. miRNA expression profiling was investigated in the kidneys of 8-month-old Zucker diabetic fatty (ZDF) rats during overt nephropathy. Localisation of the most upregulated miRNA was established by in situ hybridisation. The candidate miRNA target was identified by in silico analysis and its expression documented in the diabetic kidney associated with fibrotic markers. Cultured tubule cells served to assess which of the profibrogenic stimuli acted as a trigger for the overexpressed miRNA, and to investigate underlying epigenetic mechanisms. In ZDF rats, miR-184 showed the strongest differential upregulation compared with lean rats (18-fold). Tubular localisation of miR-184 was associated with reduced expression of lipid phosphate phosphatase 3 (LPP3) and collagen accumulation. Transfection of NRK-52E cells with miR-184 mimic reduced LPP3, promoting a profibrotic phenotype. Albumin was a major trigger of miR-184 expression. Anti-miR-184 counteracted albumin-induced LPP3 downregulation and overexpression of plasminogen activator inhibitor-1. In ZDF rats, ACE-inhibitor treatment limited albuminuria and reduced miR-184, with tubular LPP3 preservation and tubulointerstitial fibrosis amelioration. Albumin-induced miR-184 expression in tubule cells was epigenetically regulated through DNA demethylation and histone lysine acetylation and was accompanied by binding of NF-kappa B p65 subunit to miR-184 promoter. These results suggest that miR-184 may act as a downstream effector of albuminuria through LPP3 to promote tubulointerstitial fibrosis, and offer the rationale to investigate whether targeting miR-184 in association with albuminuria-lowering drugs may be a new strategy to achieve fully anti-fibrotic effects in diabetic nephropathy

    Radio morphology-accretion mode link in FRII low-excitation radio galaxies

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    Fanaroff-Riley II low-excitation radio galaxies (FRII-LERGs) are characterized by weak nuclear excitation on pc-scales and by properties typical of powerful FRIIs (defined as high-excitation, hereafter HERGs/BLRGs) on kp-scales. Since a link between the accretion properties and the power of the produced jets is expected both from theory and observations, their nature is still debated. In this work we investigate the X-ray properties of a complete sample of 19 FRII-LERGs belonging to the 3CR catalog, exploiting Chandra and XMM-Newton archival data. We also analyze 32 FRII-HERGs/BLRGs with Chandra data as a control sample. We compared FRII-LERG and FRII-HERG/BLRG X-ray properties and optical data available in literature to obtain a wide outlook of their behavior. The low accretion rate estimates for FRII-LERGs, from both X-ray and optical bands, allow us to firmly reject the hypothesis for that they are the highly obscured counterpart of powerful FRII-HERGs/BLRGs. Therefore, at least two hypothesis can be invoked to explain the FRII-LERGs nature: (i) they are evolving from classical FRIIs because of the depletion of accreting cold gas in the nuclear region, while the extended radio emission is the heritage of a past efficiently accreting activity; (ii) they are an intrinsically distinct class of objects with respect to classical FRIs/FRIIs. Surprisingly, in this direction a correlation between accretion rates and environmental richness is found in our sample. The richer the environment, the more inefficient is the accretion. In this framework, the FRII-LERGs are intermediate between FRIs and FRII-HERGs/BLRGs both in terms of accretion rate and environment.Comment: 13 pages, 7 figures, Accepted for publication in MNRA

    Large-scale radio morphology and nuclear accretion in FRII-low-excitation radio galaxies

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    Radio galaxies (RGs) are among the most energetic manifestation of the AGN phenomenon and, as such, are extraordinarily relevant to address important unknowns relating accretion and ejection, and to investigate the role of the surrounding environment in shaping the radio morphology. The best candidates for this pioneering study are the RGs classified as FRII-LERGs, since they show both a radio morphology typical of powerful RGs (expected to have a standard accretion disc) and have an inefficient engine, as suggested by their optical spectra. In this work we study the X-ray properties of all the FRII-LERGs of the 3CR sample at z<0.3 testing three possible scenarios: (i) FRII-LERGs are recently switched-off high-excitation RGs (HERGs) with efficient accretion disc; (ii) FRII-LERGs are strongly absorbed HERGs; (iii) FRII-LERGs are inefficient accretors and their large-scale radio emission is mainly determined by the environment. These results will be further supplemented by multi-wavelength observations, with particular attention to the radio band
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