Stima dei parametri di modelli idrologici mediante ottimizzazione dell’utilità

Tradizionalmente, l'obiettivo della calibrazione di un modello afflussi-deflussi è sempre stato quello di ottenere un set di parametri (o una distribuzione di probabilità dei parametri) che massimizzasse l'adattamento dei dati simulati alla realtà osservata, trattando parzialmente le finalità applicative del modello. Nel lavoro di tesi viene proposta una metodologia di calibrazione che trae spunto dell'evidenza che non sempre la corrispondenza tra dati osservati e simulati rappresenti il criterio più appropriato per calibrare un modello idrologico. Ai fini applicativi infatti, può risultare maggiormente utile una miglior rappresentazione di un determinato aspetto dell'idrogramma piuttosto che un altro. Il metodo di calibrazione che viene proposto mira a valutare le prestazioni del modello stimandone l'utilità nell'applicazione prevista. Tramite l'utilizzo di opportune funzioni, ad ogni passo temporale viene valutata l'utilità della simulazione ottenuta. La calibrazione viene quindi eseguita attraverso la massimizzazione di una funzione obiettivo costituita dalla somma delle utilità stimate nei singoli passi temporali. Le analisi mostrano come attraverso l'impiego di tali funzioni obiettivo sia possibile migliorare le prestazioni del modello laddove ritenute di maggior interesse per per le finalità applicative previste.

Water and sediments geochemistry and elemental fluxes on a Large Dam: case study of Ridracoli reservoir.

Since the study of Large Dam Reservoirs is of worldwide interest, in this PhD project we investigated the Ridracoli reservoir, one of the main water supply in Emilia-Romagna (north-eastern Italy). This work aims to characterize waters and sediments to better understand their composition, interactions and any process that occurs, for a better geochemical and environmental knowledge of the area. Physical and chemical analyses on the water column have shown an alternation of stratification and mixing of water in the reservoir’s water body due to seasonal variations in temperature and density. In particular, it was observed the establishment, in late summer, of anoxic conditions at the bottom, which in turn affects the concentration and mobility of some elements of concern (e.g. Fe and Mn) for the water quality. Sediments within the reservoir and from surrounding areas were analysed for organic matter, total inorganic composition and grain size, assessing the inter-element relationship, grain size, geological background and damming influences on their chemistry, through descriptive statistics, Principal Component Analysis and Cluster Analysis. The reservoir’s area was also investigated by pseudo total composition (Aqua Regia digestion), degree of elements extractability, and enrichment factors, then analysed and compared to limits by law and literature. Sediment cores, interstitial waters, and benthic chamber data from the bottom were of great interest due to organic matter degradation, early diagenesis, mineral formation at water-sediment interface and observed flows. Finally, leaching test and extraction procedures, of environmental interest, showed peculiar partitioning, both regarding spatial and in-depth distribution, and the absence of pollution. Collectively, our results are useful for the comprehension of processes that occur in water and sediments of Ridracoli reservoir, providing important knowledges on the site that could be relevant for the management of the resource and the planning of future interventions.

Revisione critica dei risultati e nuovi algoritmi decisionali sulla chirurgia dell'OSAS

Obstructive sleep apnoea/hypopnoea syndrome (OSAHS) is the periodic reduction or cessation of airflow during sleep. The syndrome is associated whit loud snoring, disrupted sleep and observed apnoeas. Surgery aims to alleviate symptoms of daytime sleepiness, improve quality of life and reduce the signs of sleep apnoea recordered by polysomnography. Surgical intervention for snoring and OSAHS includes several procedures, each designed to increase the patency of the upper airway. Procedures addressing nasal obstruction include septoplasty, turbinectomy, and radiofrequency ablation (RF) of the turbinates. Surgical procedures to reduce soft palate redundancy include uvulopalatopharyngoplasty with or without tonsillectomy, uvulopalatal flap, laser-assisted uvulopalatoplasty, and RF of the soft palate. More significant, however, particularly in cases of severe OSA, is hypopharyngeal or retrolingual obstruction related to an enlarged tongue, or more commonly due to maxillomandibular deficiency. Surgeries in these cases are aimed at reducing the bulk of the tongue base or providing more space for the tongue in the oropharynx so as to limit posterior collapse during sleep. These procedures include tongue-base suspension, genioglossal advancement, hyoid suspension, lingualplasty, and maxillomandibular advancement. We reviewed 269 patients undergoing to osas surgery at the ENT Department of Forlì Hospital in the last decade. Surgery was considered a success if the postoperative apnea/hypopnea index (AHI) was less than 20/h. According to the results, we have developed surgical decisional algorithms with the aims to optimize the success of these procedures by identifying proper candidates for surgery and the most appropriate surgical techniques. Although not without risks and not as predictable as positive airway pressure therapy, surgery remains an important treatment option for patients with obstructive sleep apnea (OSA), particularly for those who have failed or cannot tolerate positive airway pressure therapy. Successful surgery depends on proper patient selection, proper procedure selection, and experience of the surgeon. The intended purpose of medical algorithms is to improve and standardize decisions made in the delivery of medical care, assist in standardizing selection and application of treatment regimens, to reduce potential introduction of errors. Nasal Continuous Positive Airway Pressure (nCPAP) is the recommended therapy for patients with moderate to severe OSAS. Unfortunately this treatment is not accepted by some patient, appears to be poorly tolerated in a not neglible number of subjects, and the compliance may be critical, especially in the long term if correctly evaluated with interview as well with CPAP smart cards analysis. Among the alternative options in Literature, surgery is a long time honoured solution. However until now no clear scientific evidence exists that surgery can be considered a really effective option in OSAHS management. We have design a randomized prospective study comparing MMA and a ventilatory device (Autotitrating Positive Airways Pressure – APAP) in order to understand the real effectiveness of surgery in the management of moderate to severe OSAS. Fifty consecutive previously full informed patients suffering from severe OSAHS were enrolled and randomised into a conservative (APAP) or surgical (MMA) arm. Demographic, biometric, PSG and ESS profiles of the two group were statistically not significantly different. One year after surgery or continuous APAP treatment both groups showed a remarkable improvement of mean AHI and ESS; the degree of improvement was not statistically different. Provided the relatively small sample of studied subjects and the relatively short time of follow up, MMA proved to be in our adult and severe OSAHS patients group a valuable alternative therapeutical tool with a success rate not inferior to APAP.

Calibrazione di modelli idrologici con algoritmi multiobiettivo

Traditional procedures for rainfall-runoff model calibration are generally based on the fit of the individual values of simulated and observed hydrographs. It is used here an alternative option that is carried out by matching, in the optimisation process, a set of statistics of the river flow. Such approach has the additional, significant advantage to allow also a straightforward regional calibration of the model parameters, based on the regionalisation of the selected statistics. The minimisation of the set of objective functions is carried out by using the AMALGAM algorithm, leading to the identification of behavioural parameter sets. The procedure is applied to a set of river basins located in central Italy: the basins are treated alternatively as gauged and ungauged and, as a term of comparison, the results obtained with a traditional time-domain calibration is also presented. The results show that a suitable choice of the statistics to be optimised leads to interesting results in real world case studies as far as the reproduction of the different flow regimes is concerned.

Ruolo dei glicosaminoglicani su struttura e funzione dei crimps nei tendini e nei legamenti

The biomechanical roles of both tendons and ligaments are fulfilled by extracellular matrix of these tissues. In particular, tension is mainly transmitted and resisted by fibrous proteins (collagen, elastin), whereas compressive load is absorbed by water-soluble glycosaminoglycans (GAGs). GAGs spanning the interfibrillar spaces and interacting with fibrils also seem to play a part in transmitting and resisting tensile stresses. Apart from different functional roles and collagen array, tendons and ligaments share the same basic structure showing periodic undulations of collagen fibers or crimps. Each crimp is composed of many knots of each single fibril or fibrillar crimps. Fibrillar and fiber crimps act as shock absorbers during the initial elongation of both tendons and ligaments and assist the elastic recoil of fibrils and fibers when the tensile stress is removed. The aim of this thesis was to evaluate whether GAGs directly affect the 3D microstructural integrity of fibrillar crimp and fiber crimps in both tendons and ligaments. Achilles tendons and medial collateral ligaments of the knee from eight female Sprague-Dawley rats (90 days old) were digested with chondroitinase ABC to remove GAGs and observed under a scanning electron microscope (SEM). In addition, isolated fibrils from these tissues obtained by mechanical homogenization were analyzed by a transmission electron microscope (TEM). Both samples digested with chondroitinase ABC or mechanically disrupted still showed crimps and fibrillar crimps comparable to tissues with a normal GAGs content. All fibrils in the fibrillar crimp region always twisted leftwards, thus changing their running plane, and then sharply bent, changing their course on a new plane. These data suggest that GAGs do not affect structural integrity or fibrillar crimps functions that seem mainly related to the local fibril leftward twisting and the alternating handedness of collagen from a molecular to a supramolecular level.

Streptococcus agalactiae adapts to glucose stress conditions by modulating gene expression profile

Diabetes mellitus is considered a risk factor for Group B Streptococcus (GBS) infections. Typically, this pathology is associated to high glucose levels in the bloodstream. Although clinical evidences support this notion, the physiological mechanisms underlying GBS adaptation to such conditions are not yet defined. In the attempt to address this issue, we performed comparative global gene expression analysis of GBS grown under glucose-stress conditions and observed that a number of metabolic and virulence genes was differentially regulated. Of importance, we also demonstrated that by knocking-out the csrRS locus the transcription profile of GBS grown in high-glucose conditions was profoundly affected, with more than a third of glucose-dependent genes, including the virulence factor bibA, found to be controlled by this two-component system. Furthermore, in vitro molecular analysis showed that CsrR specifically binds to the bibA promoter and the phosphorilation increases the affinity of the regulator to this promoter region. Moreover, we demonstrated that CsrR acts as a repressor of bibA expression by binding to its promoter in vivo. In conclusion, this work by elucidating both the response of GBS to pathological glucose conditions and the underlined molecular mechanisms will set the basis for a better understanding of GBS pathogenesis.

Applications of infrared thermography in the food industry

In the last 20-30 years, the implementation of new technologies from the research centres to the food industry process was very fast. The infrared thermography is a tool used in many fields, including agriculture and food science technology, because of it's important qualities like non-destructive method, it is fast, it is accurate, it is repeatable and economical. Almost all the industrial food processors have to use the thermal process to obtain an optimal product respecting the quality and safety standards. The control of temperature of food products during the production, transportation, storage and sales is an essential process in the food industry network. This tool can minimize the human error during the control of heat operation, and reduce the costs with personal. In this thesis the application of infrared thermography (IRT) was studies for different products that need a thermal process during the food processing. The background of thermography was presented, and also some of its applications in food industry, with the benefits and limits of applicability. The measurement of the temperature of the egg shell during the heat treatment in natural convection and with hot-air treatment was compared with the calculated temperatures obtained by a simplified finite element model made in the past. The complete process shown a good results between calculated and observed temperatures and we can say that this technique can be useful to control the heat treatments for decontamination of egg using the infrared thermography. Other important application of IRT was to determine the evolution of emissivity of potato raw during the freezing process and the control non-destructive control of this process. We can conclude that the IRT can represent a real option for the control of thermal process from the food industry, but more researches on various products are necessary.

Studio degli effetti della mordenzatura con acido fluoridrico sul disilicato di litio utilizzato in odontoiatria

Scopo dello studio: valutare i cambiamenti indotti da diversi trattamenti di mordenzatura sulla morfologia superficiale e sulla microstruttura di due vetro-ceramiche a base disilicato di litio (IPS e.max® Press e IPS e.max® CAD) ed esaminarne gli effetti sia sull’adesione con un cemento resinoso che sulla resistenza alla flessione. Materiali e metodi: Settanta dischetti (12 mm di diametro, 2 mm di spessore) di ogni ceramica sono stati preparati e divisi in 5 gruppi: nessun trattamento (G1), HF 5% 20s (G2), HF 5% 60s (G3), HF 9.6% 20s (G4), HF 9.6% 60s (G5). Un campione per ogni gruppo è stato analizzato mediante profilometro ottico e osservato al SEM. Per gli altri campioni è stato determinato lo shear bond strength (SBS) con un cemento resinoso. Dopo l’SBS test, i campioni sono stati caricati fino a frattura utilizzando il piston-on-three-ball test per determinarne la resistenza biassiale alla flessione. Risultati: L’analisi morfologica e microstrutturale dei campioni ha rivelato come diversi trattamenti di mordenzatura producano delle modifiche nella rugosità superficiale che non sono direttamente collegate ad un aumento dei valori di adesione e dei cambiamenti microstrutturali che sono più rilevanti con l’aumento del tempo di mordenzatura e di concentrazione dell’acido. I valori medi di adesione (MPa) per IPS e.max® CAD sono significativamente più alti in G2 e G3 (21,28 +/- 4,9 e 19,55 +/- 5,41 rispettivamente); per IPS e.max® Press, i valori più elevati sono in G3 (16,80 +/- 3,96). La resistenza biassiale alla flessione media (MPa) è più alta in IPS e.max® CAD (695 +/- 161) che in IPS e.max® Press (588 +/- 117), ma non è non influenzata dalla mordenzatura con HF. Conclusioni: il disilicato di litio va mordenzato preferibilmente con HF al 5%. La mordenzatura produce alcuni cambiamenti superficiali e microstrutturali nel materiale, ma tali cambiamenti non ne influenzano la resistenza in flessione.

La debida imparcialidad de la Administración Tributaria

Este trabajo de investigación, tiene por objeto el análisis de la posición de la Administración Tributaria en el marco conceptual de la relación jurídico-tributaria, y de las implicaciones que de cara al principio de imparcialidad, pueden tener los diversos posicionamientos conceptuales que de ésta se hagan, en procura de alcanzar una sana circunscripción de la naturaleza y el enfoque que se puede esperar y exigir de una Administración Tributaria moderna. Para lograrlo, se analizan los orígenes y alcances de la relación jurídico-tributaria, así como las múltiples y hasta divergentes acepciones doctrinales acerca de los actores directamente involucrados por el ordenamiento en tal relación, con especial atención a las divergentes acepciones del concepto de sujeto activo, y de la identificación de la Administración Tributaria en ese rol. Se aborda el estudio del panorama, las condiciones, el papel y los objetivos de la Administración Tributaria en la dinámica actual de la relación obligacional tributaria, de frente a la hipótesis de una concepción alternativa y más eficiente de la Administración Tributaria, como un garante del cumplimiento del Derecho Tributario, y ya no simplemente como un garante de la recaudación tributaria, lo que lleva casualmente a una revisión del modelo de “Relación Cooperativa” entre sujetos pasivos y Administración Tributaria, como un posible nuevo enfoque del paradigma de participación de ésta última en la relación, con evidencias funcionales y ejemplificativas, de institutos jurídicos tendentes a un nuevo paradigma, actualmente vigentes en España, Italia y Holanda.

Nanostructured Systems for Electrocatalysis of Reduction Reactions for Energy Conversion Applications

Oxygen Reduction Reaction (ORR) requires a platinum-based catalyst to reduce the activation barrier. One of the most promising materials as alternative catalysts are carbon-based, graphene and carbon nanotubes (CNT) derivatives. ORR on a carbon-based substrate involves the less efficient two electrons process and the optimal four electrons process. New synthetic strategies to produce tunable graphene-based materials utilizing graphene oxide (GO) as a base inspired the first part of this work. Hydrogen Evolution Reaction (HER) is a slow process requiring also platinum or palladium as catalyst. In the second part of this work, we develop and use a technique for Ni nanoparticles electrodeposition using NiCl2 as precursor in the presence of ascorbate ligands. Electrodeposition of nano-nickel onto flat glassy carbon (GC) and onto nitrogen-doped reduced graphene oxide (rGO-N) substrates are studied. State of the art catalysts for CO2RR requires rare metals rhenium or rhodium. In recent years significant research has been done on non-noble metals and molecular systems to use as electro and photo-catalysts (artificial photosynthesis). As Cu-Zn alloys show good CO2RR performance, here we applied the same nanoparticle electrosynthesis technique using as precursors CuCl2 and Cl2Zn and observed successful formation of the nanoparticles and a notable activity in presence of CO2. Using rhenium complexes as catalysts is another popular approach and di-nuclear complexes have a positive cooperative effect. More recently a growing family of pre-catalysts based on the earth-abundant metal manganese, has emerged as a promising, cheaper alternative. Here we study the cooperative effects of di-nuclear manganese complexes derivatives when used as homogeneous electrocatalysts, as well as a rhenium functionalized polymer used as heterogeneous electrocatalyst.

Exploiting spectrally resolved satellite observations to assess the performance of climate models

The accurate representation of the Earth Radiation Budget by General Circulation Models (GCMs) is a fundamental requirement to provide reliable historical and future climate simulations. In this study, we found reasonable agreement between the integrated energy fluxes at the top of the atmosphere simulated by 34 state-of-the-art climate models and the observations provided by the Cloud and Earth Radiant Energy System (CERES) mission on a global scale, but large regional biases have been detected throughout the globe. Furthermore, we highlighted that a good agreement between simulated and observed integrated Outgoing Longwave Radiation (OLR) fluxes may be obtained from the cancellation of opposite-in-sign systematic errors, localized in different spectral ranges. To avoid this and to understand the causes of these biases, we compared the observed Earth emission spectra, measured by the Infrared Atmospheric Sounding Interferometer (IASI) in the period 2008-2016, with the synthetic radiances computed on the basis of the atmospheric fields provided by the EC-Earth GCM. To this purpose, the fast σ-IASI radiative transfer model was used, after its validation and implementation in EC-Earth. From the comparison between observed and simulated spectral radiances, a positive temperature bias in the stratosphere and a negative temperature bias in the middle troposphere, as well as a dry bias of the water vapor concentration in the upper troposphere, have been identified in the EC-Earth climate model. The analysis has been performed in clear-sky conditions, but the feasibility of its extension in the presence of clouds, whose impact on the radiation represents the greatest source of uncertainty in climate models, has also been proven. Finally, the analysis of simulated and observed OLR trends indicated good agreement and provided detailed information on the spectral fingerprints of the evolution of the main climate variables.