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Effect of the ligands of thyroid hormone receptor on non-alcoholic fatty liver disease
Get PDFThe term non-alcoholic fatty liver disease (NAFLD) has been used as a general name for conditions ranging from simple steatosis to steatohepatitis, advanced fibrosis and cirrhosis. End-stage NAFLD cirrhosis carries a substantial risk for early hepatocellular carcinoma development. Therefore, there is an increasing need for new therapeutic approaches for the treatment of this liver disease. Here, we examined the effect of the thyroid hormone triiodothyronine (T3) and the agonist of the thyroid hormone receptor β isoform (TRβ), GC-1, on fatty liver and steatohepatitis induced in rodents by a choline-deficient, methionine-restricted (CMD) diet.
Male Fischer rats fed the CMD diet for 1 week developed a marked fatty liver and mild hepatitis. Concurrent administration of T3 resulted in a complete prevention of the fatty change associated with increased mitochondrial and peroxisomal fatty acid beta-oxidation. To investigate whether T3 could also reverse fully established fatty liver, rats were fed the CMD diet for 10 weeks and then cofed T3 for 1 week. Coadministration of T3 resulted in a complete regression of liver steatosis associated with a decrease of lipid peroxidation, cyclooxygenase-2 expression, and activation of phospho-STAT3 and phospho-SAPK/JNK. Finally, additional experiments showed that GC-1, which has no significant side effects on heart rate, prevented and reverted CMD-induced fat accumulation.
These results indicate that TR agonists have the potential to inhibit or reverse hepatic steatosis induced by a nutritional model
Sincronizzazione dei sistemi di misura distribuiti nelle reti elettriche.
Get PDFI recenti cambiamenti nella configurazione dei sistemi di distribuzione dell’energia elettrica comportano l’esigenza di sviluppare sistemi di misura distribuiti su larga scala per affrontare lo studio e l’analisi di problematiche di gestione, monitoraggio e controllo differenti da quelle tradizionalmente considerate. In questo lavoro di tesi è stata affrontata la definizione e lo sviluppo di metodologie di misura finalizzate al monitoraggio delle reti elettriche di distribuzione. L’analisi condotta ha riguardato prevalentemente i sistemi di misura per i fasori sincronizzati, che oggigiorno trovano larga diffusione per molteplici applicazioni di gestione e controllo nei sistemi elettrici
Parco Naturale Regionale Molentargius-Saline. Flora: stato attuale e confronto con le situazioni preesistenti
No full textThis work has been realized in order to bring a meaningful contribution to the acquaintance of all the events and procedures carried out to the final completion of the Reclaiming Plan about the Molentargius area during the years besides the study of the Molentargius’ flora, which have contributed to the Park’s birth. The punctual analysis of every action realized allows to better understand the effects that such processes has created in the floristic and vegetable ecosystem. In particular the bibliographical and herbarium researches have been deepened to obtain a complete panorama of the pre-existent activities about the vegetable elements of the Molentargius area. On field analyses, through relief carried out directly in field, have allowed to characterize the flora currently present in the Park made up of 498 “taxonomic units” (368 species, 128 subspecies, 2 different varieties, distributed in 69 families and 276 genera. Such data have supplied the base for different elaborations and comparison among vegetable species. The analysis of the biological spectrum puts in relief the character of strong Mediterranean component of the Molentargius area, thanks to the high presence of the Therophytes that approximately constitute 57% of the vegetable patrimony; the Mediterranean component of the flora appears also evident from the analysis of the chorological categories in which the Mediterranean elements, also comprehensive of the endemic species, represent about 68% of the vegetable species examined
Dynamics of ash eruptions at Vesuvius
Get PDFIn the recent years, continuous ash emission activity, related to mid-low intensity, long lasting eruptions, has been increasingly described to occur at different volcanoes worldwide. Focusing on this type of deposits, a retrospective analysis of the stratigraphic successions at Vesuvius revealed that such type of eruptions have occurred repeatedly in the last 4000 years of activity. This type of activity has been overlooked in the past and the mechanism of ash production in these eruptions is not yet clear. The detailed study of the deposits suggests that these eruptions are dominated by discrete phases of repeated emission of a highly fragmented mixture, alternated with violent strombolian episodes. In this study we present morphological, textural and compositional data on the products of two ash eruptions representative of the whole variability of this activity at Vesuvius (Italy), occurred in the periods between the “Avellino” and “Pompeii” Pumice eruptions (AP3, 2,710±60 years B.P.) and after the 512 A.D. eruption, (AS1a). Juvenile fragments from different ash layers throughout the studied stratigraphic sections were fully characterized in terms of external morphology, particle outline parameterization, groundmass texture (in terms of Crystal and Vesicle Size Distributions) and glass composition. Volcanic ash holds information about magma dynamics within the volcanic conduit, where fragmentation occurs and eruption style is decided. Results of our investigations have been interpreted in terms of fragmentation processes, transport and dispositional mechanisms, dynamics of magma ascent ant timing of the eruption. The methodology of ash analysis used for this study has also important implications for tephrochronological studies, adding a complete parameterization of physical and textural properties of the ash to the routinely used compositional data
Assessing uncertainty propagation of precipitation input in hydrometeorological ensemble forecasting systems
Get PDFThe aim of the thesis is the assessment of precipitation input uncertainty into hydrological response in hydrometeorological ensemble systems for flood prediction.
The study has been preliminary focused on the development of a hydrometeorological system that couples a statistical precipitation downscaling model, known as STRAIN, with a fully-distributed hydrological model, known as tRIBS.
In a subsequent part of the research, a rigorous method has been designed to test the consistency hypothesis (i.e. ensemble and observations are drawn from the same distribution) of the ensemble precipitation fields generated by downscaling models. The verification procedure has been tested by means of numerical experiments. Results permit us to conclude that: (i) ensemble members generated using model parameters estimated on the observed event are overdispersed; (ii) the adoption of a single calibration relation linking model parameters and coarse meteorological observable can lead to the generation of consistent ensemble members; (iii) when a single calibration relation is not able to explain observed events variability, storm-specific calibration relation should be adopted to return consistent forecasts.
Finally, in the last part of the work, a rigorous method has been developed to assess consistency of ensemble streamflows produced by hydrometeorological systems. The method has been tested with numerical experiments using the prediction system designed in the preliminary phase of the study with the purpose of evaluating the propagation of uncertainty of downscaled precipitation input into hydrological response.
The innovative aspects of the thesis rely on (i) the development of rigorous verification methods for ensemble outputs of hydrometeorological systems; and (ii) the application of these procedure on a great number of events in order to draw statistically significant conclusions
The Communicational Side of Open Source Communities
Get PDFCommunication is a fundamental value of software development teams, especially in Open Source(OP) communities, in fact, is a quite complex network of individuals having different roles and responsibilities, who can be looked upon as volunteers who spend their time creating and improving software. These people taking part in OS Software development use to share knowledge among themselves, exchange information and creative a collaborative environment. To coordinate and improve communication of these teams dis-located all over the world and use to work at different times and ways, it is necessary to predispose and utilize specific tools. This research study was born with the proposal to individuate and evaluate communication among members of OS communities analysing different development teams. The starting point is an academic software development project: Metodologie Agili Distribuite (Agile Distribuite Metodologies, MAD) project. This case study, performed at University of Cagliari, was made up of two well defined software development phases. The first one performed within an almost pure XP co-located environment, the second one involving a 20-programmers distributed team. The main goal of this experience was to show how a pure XP approach evolves while passing from a co-located to a distribute team
La valutazione di pericolosità geologica a scala locale. Zonazione dei versanti di Muravera e della valle del Rio Pardu
Get PDFL’applicazione di un metodo di valutazione della pericolosità geologica dei versanti finalizzata alla produzione delle cartografie di pericolosità inserite all’interno di uno strumento di pianificazione territoriale, introduce una serie di problematiche che non sono ravvisabili quando lo stesso processo è effettuato solo a scopo speculativo. Partendo da tali presupposti, gli obiettivi prioritari di questo lavoro sono:
proporre una metodologia di valutazione della pericolosità geologica dei versanti che risponda alle reali e concrete esigenze della pianificazione territoriale a livello locale. Per la produzione della carta di pericolosità geologica è stata utilizzata una metodologia di indicizzazione dei fattori di suscettività franosa (Overlay Mapping), nella variante proposta da Dovera, Mancini, Salis (2000), seguendo le linee guida del PAI con alcune modifiche ed integrazioni che la rendono idonea alla valutazione di pericolosità a scala locale. A tale scopo si è provveduto a sperimenta nell'area di Muravera, comune ubicato sulla costa sud-orientale della Sardegna, una specifica metodologia di valutazione e pesatura del parametro litologico che rendesse meno soggettivo il processo di valutazione della pericolosità;
confrontare i risultati delle elaborazioni effettuate sulla stessa area, eseguite con metodi di zonazione di pericolosità franosa differenti: il metodo di indicizzazione dei fattori di suscettività franosa (Overlay Mapping), un metodo statistico e uno basato sulle reti neurali. Per effettuare questo confronto si è scelto di lavorare presso un’area in cui i problemi d’instabilità dei versanti sono rilevanti e conosciuti, quella della valle del Rio Pardu, nel territorio comunale di Gairo, in Ogliastra
La terra cruda dei Campidani, del Cixerri e del Sarrabus
No full textIl manuale si pone l'obbiettivo di contribuire alla definizione di linee guida per il recupero dell'architettura di base storico-tradizionale. Vengono trattati una serie di argomenti tra cui: i processi territoriali di formazione e trasformazione del patrimonio storico, l'articolazione spaziale della casa storica, i caratteri e gli elementi della fabbrica edilizia, linnee guide per il recupero delle diverse forme di degrado in atto
Sugli spazi omogenei di dimensione tre SO(2) - isotropi
No full textIn this thesis we studied some problems from the theory of the submanifolds
of the three-dimensional Riemannian manifolds. Our intention is to evaluate
which properties of the submanifolds depend by the dimension of the group
of isometries. We considered a two-parameter family of three-dimensional
Riemannian manifolds (M, ds2
ℓ,m), endowed with the Cartan - Vranceanu
metrics. These metrics can be found in the classification of 3-dimensional
homogeneous metrics given by L. Bianchi. Their geometric interest lies in
the following fact: the family of metrics includes all 3-dimensional homogeneous
metrics whose group of isometries has dimension 4 or 6, except for
those of constant negative sectional curvature. The group of isometries of
these spaces has a subgroup isomorphic to the group SO(2), so there exist
surfaces of revolution around z-axis. We explicitly obtained the Lie algebra
of the Killing vector fields and thus the group of isometries for the C-V
metrics. We determined the equations of the geodesics using the Killing
vector fields and obtain explicitly the equation of the surface which con-
tains the geodesics. After having determined the totally geodesics surfaces
isometrically immersed in the C-V spaces, we studied the totally umbili-
cal submanifolds of these spaces, proving that the only totally umbilical
submanifolds are totally geodesic. We found the geodesics for the SO(2)-
invariant surfaces of the Cartan-Vranceanu spaces, deduced the conditions
that meridians and parallels must satisfy in order to be geodesics and show
the analogies with the euclidian case