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Climate variability through Koopman theory
No full textThe Earth's climate is a complex, nonlinear interplay of processes operating across a wide range of scales, giving rise to dynamic patterns of variability. Large-scale modes, such as ENSO, the Pacific Decadal Oscillation, and the North Atlantic Oscillation, play fundamental roles in shaping global climate conditions. Among these, ENSO is the dominant coupled atmosphere–ocean mode, driving global teleconnections that affect ecosystems, agriculture, and extreme events. Understanding and forecasting ENSO is therefore critical for improving climate resilience and sustainability. Traditional forecasting methods, including General Circulation Models, face limitations in simulating complex dynamics, such as ENSO. Simpler empirical approaches like Linear Inverse Models demonstrate notable skill, but rely on linear approximations which cannot fully capture its complexity. In this context, Koopman theory offers a powerful alternative, transforming nonlinear dynamics into a linear framework on a observables space, and enabling the identification of coherent structures and dominant modes within the system. This thesis applies Koopman theory to advance the understanding and predictability of ENSO and broader climate variability. Using kernel-Extended Dynamic Mode Decomposition, the study estimates Koopman spectra from tropical and global SST data. Key objectives include identifying stationary subspaces, linking dominant Koopman modes to relevant modes of climate variability, and evaluating the forecasting skill of Koopman-based methods. A new framework, Koopman Ensemble Forecasts, is proposed to address sensitivities to data record lengths, while the Residual DMD algorithm introduces an approach for assessing the reliability of Koopman modes. The findings of this thesis contribute to both fundamental and applied climate science. By addressing the structure of ENSO-related modes, this work deepens the understanding of its dynamics and highlights the potential of Koopman methods to enhance seasonal forecasting and the study of climate fluctuations. These results offer promising avenues for advancing data-driven climate modeling and developing robust tools for investigating climate variability and predictability
New biomaterials for packaging: a green approach to biopolymers and biocomposites
No full textThe impellent global environmental issues related to plastic materials can be addressed by following two different approaches: i) the development of synthetic strategies towards novel bio-based polymers, deriving from biomasses and thus identifiable as CO2-neutral materials, and ii) the development of new plastic materials, such as biocomposites, which are bio-based and biodegradable and therefore able to counteract the accumulation of plastic waste.
In this framework, this dissertation presents extensive research efforts have been devoted to the synthesis and characterization of polyesters based on various bio-based monomers, including ω-pentadecalactone, vanillic acid, 2,5-furan dicarboxylic acid, and 5-hydroxymethylfurfural. With the aim of achieving high molecular weight polyesters, different synthetic strategies have been used as melt polycondensation, enzymatic polymerization, ring-opening polymerization and chain extension reaction. In particular, poly(ethylene vanillate) (PEV), poly(ω-pentadecalactone) (PPDL), poly(ethylene vanillate-co-pentadecalactone) (P(EV-co-PDL)), poly(2-hydroxymethyl 5-furancarboxylate) (PHMF), poly(ethylene 2,5-furandicarboxylate) (PEF) with different amount of diethylene glycol (DEG) unit amount, poly(propylene 2,5-furandicarboxylate) (PPF), poly(hexamethylene 2,5-furandicarboxylate), (PHF) have been prepared and extensively characterized. To improve the lacks of poly(hydroxybutyrate-co-valerate) (PHBV), its minimal formulations with natural additives and its blending with medium chain length PHAs (mcl-PHAs) have been tested.
Additionally, this dissertation presents new biocomposites based on polylactic acid (PLA), poly(butylene succinate) (PBS), and PHBV, which are polymers both bio-based and biodegradable. To maintain their biodegradability only bio-fillers have been taken into account as reinforcing agents. Moreover, the commitment to sustainability has further limited the selection and led to the exclusive use of agricultural waste as fillers.
Detailly, biocomposites have been obtained and discussed by using the following materials: PLA and agro-wastes like tree pruning, potato peels, and hay leftovers; PBS and exhausted non-compliant coffee green beans; PHBV and industrial starch extraction residues
Hypertensive disorders of pregnancy and long-term cardiovascular health and outcomes
No full textIntroduction
The maternal vasculature undergoes significant adaptations during pregnancy to meet the increased metabolic demands of the developing fetus. These adaptations include increased cardiac output and blood volume, as well as reduced systemic vascular resistance. In Hypertensive disorders of pregnancy (HDP) there is an impaired cardiovascular adaptation to pregnancy with effects extending beyond pregnancy. In the present study we aimed to characterize long-term cardiovascular status of women who suffered from HDP.
Methods
Fifty-eight women who attended at least one post-partum visit and a follow-up visit after at least 5 years from delivery were enrolled in the study. Exclusion criteria included multiple pregnancy, fetal genetic or congenital abnormalities, maternal history of organ transplantation, or chronic renal failure (eGFR≤45ml/min/1.73m2). In the follow-up visit participants underwent a complete cardiovascular assessment including echocardiography and multiparametric vascular function assessment.
Results and Discussion
Two major cardiovascular events, one stroke and one myocardial infarction, occurred both in women with index-pregnancy complicated by preeclampsia (PE). While not statistically significant, women with HDP-non-PE and PE displayed a trend towards an increased risk of developing composite cardiovascular outcome, and women with PE tended to experience it sooner. Nearly half of the women with a history of HDP, whether PE or HDP-non-PE, developed chronic hypertension. Some women also developed hyperuricemia, chronic kidney disease (CKD), and type 2 diabetes at follow- up, most of them had a previous history of PE. Structural and functional cardiac changes were observed in a few cases, especially among women with PE, and vascular dysfunction was more common in women with a history of HDP compared to those with normotensive pregnancies. Results of the present study adds on literature on long-term cardiovascular impact of HDP and further emphasize the importance of a timely follow-up of women who suffered from HDP and particularly PE
Development and testing of methodologies for the control and diagnosis of innovative combustion systems
No full textIn pursuit of aligning with the European Union's ambitious target of achieving a carbon-neutral economy by 2050, researchers, vehicle manufacturers, and original equipment manufacturers have been at the forefront of exploring cutting-edge technologies for internal combustion engines. The introduction of these technologies has significantly increased the effort required to calibrate the models implemented in the engine control units. Consequently the development of tools that reduce costs and the time required during the experimental phases, has become imperative.
Additionally, to comply with ever-stricter limits on 〖"CO" 〗_"2" emissions, it is crucial to develop advanced control systems that enhance traditional engine management systems in order to reduce fuel consumption. Furthermore, the introduction of new homologation cycles, such as the real driving emissions cycle, compels manufacturers to bridge the gap between engine operation in laboratory tests and real-world conditions.
Within this context, this thesis showcases the performance and cost benefits achievable through the implementation of an auto-adaptive closed-loop control system, leveraging in-cylinder pressure sensors in a heavy-duty diesel engine designed for mining applications. Additionally, the thesis explores the promising prospect of real-time self-adaptive machine learning models, particularly neural networks, to develop an automatic system, using in-cylinder pressure sensors for the precise calibration of the target combustion phase and optimal spark advance in a spark-ignition engines.
To facilitate the application of these combustion process feedback-based algorithms in production applications, the thesis discusses the results obtained from the development of a cost-effective sensor for indirect cylinder pressure measurement. Finally, to ensure the quality control of the proposed affordable sensor, the thesis provides a comprehensive account of the design and validation process for a piezoelectric washer test system
Assessing citizenship competences in vocational education and training: the development of tools to promote formative assessment
No full textLa tesi presenta una ricerca di dottorato dedicata alla valutazione della “Competenza di cittadinanza”, introdotta nel 2020 nei percorsi di Istruzione e Formazione Professionale (IeFP). L’esito del lavoro è rappresentato dall’elaborazione di strumenti valutativi dedicati a questa competenza.
A partire dall’analisi dei bisogni educativi dei contesti di IeFP, è stato formulato un quadro teorico comprendente: le teorie sull’educazione civica, l’approccio per competenze in educazione e la valutazione delle competenze trasversali e di cittadinanza.
La ricerca empirica che ne è seguita si è articolata cercando di rispondere alle seguenti domande di ricerca:
1) Come è stata accolta l’introduzione della Competenza di cittadinanza da chi opera a vari livelli nei contesti di IeFP?
2) È possibile sviluppare degli strumenti di valutazione per la Competenza di cittadinanza su misura dei bisogni degli enti formativi?
3) L’utilizzo di questi strumenti può promuovere una prospettiva formativa della valutazione?
Il progetto di ricerca si colloca in una prospettiva metodologica ispirata ai metodi misti e al paradigma pragmatista. Il disegno è suddiviso in tre fasi. La fase iniziale, attraverso interviste aperte e semi-strutturate, ha cercato di ricostruire l’esperienza di chi opera nella IeFP rispetto all’introduzione della Competenza di cittadinanza. La seconda fase è consistita nello sviluppo e nella validazione su un campione di studenti (n = 377) di un questionario di autovalutazione e di una rubrica valutativa. La terza fase della ricerca era volta alla ricostruzione dell’esperienza d’uso degli strumenti valutativi da parte dei formatori, con particolare attenzione alle possibili ricadute formative associate all’impiego degli strumenti.
I risultati della ricerca hanno messo in evidenza che i formatori della IeFP ritengono difficile valutare la Competenza di cittadinanza. L’introduzione di strumenti valutativi inediti sembra poter promuovere una prospettiva formativa della valutazione, creando nuove opportunità di apprendimento e favorendo la riflessione di formatori e formatrici rispetto alle proprie strategie didattico-valutative.This thesis presents doctoral research dedicated to the assessment of the "Citizenship competence", introduced in 2020 in Vocational Education and Training (VET) pathways. The outcome of the research is the development of assessment tools dedicated to this competence.
Starting from the analysis of the educational needs of the IeFP contexts, a theoretical framework was formulated, including theories of civic education, the competence approach in education, and the evaluation of transversal and civic competences.
The empirical research was structured in an attempt to answer the following research questions:
1) How has the introduction of Citizenship competence been received by those working at different levels in IeFP contexts?
2) Is it possible to develop assessment tools for Citizenship competence tailored to the needs of training institutions?
3) The use of these tools can promote a formative perspective on assessment?
The research project is set within a methodological perspective inspired by mixed methods and the pragmatist paradigm. The design is divided into three phases. The first phase, through open and semi-structured interviews, aimed at reconstructing the experiences of those working in VET concerning the implementation of Citizenship competence. The second phase involved developing and validating a self-assessment questionnaire and rubric with a sample of students (n=377). The third phase of the research aimed at reconstructing the teachers' experiences in using the assessment tools, with a focus on the possible pedagogical spin-offs associated with the use of the tools.
Research results showed that VET trainers find it difficult to assess Citizenship competence. The introduction of new assessment tools seems to be able to promote a formative perspective of assessment, create new learning opportunities and encourage teachers to reflect on their own teaching and assessment strategies
Development of a botanical-based feed additive to manage weaning stress in piglets
No full textWeaning stress represents a persistent condition with long-term detrimental effects on piglets. It stimulates inflammation and oxidation, while enterotoxigenic Escherichia coli (ETEC) can overgrow and trigger diarrhea. Historically, weaning piglets’ health was supported by antibiotics (AB) and/or pharmacological zinc oxide (ZnO). However, their uncontrolled use caused resistance spread and environmental pollution. Botanicals represent a wide class of compounds that possess beneficial effects and qualify as novel tools to manage weaning stress in piglets.
The aim of this thesis was to develop a new botanical-based feed additive to support piglets at weaning, as an alternative to antibiotics and ZnO. Microbiology and cell culture experiments allowed to find selected botanicals that were efficacious in controlling ETEC growth and virulence, and supporting intestinal cells health during ETEC infections. The optimized combination of botanicals (BOT) was further validated in vitro: in enterocytes and hepatocytes, BOT displayed a robust activity against acute and chronic stress triggered by inflammatory and ETEC challenges. Its mechanism of action involved cellular integrity protection, inflammatory response reduction, oxidative status enhancement, and susceptibility to ETEC decrease.
BOT was then supplemented in the diet of weaning piglets and its beneficial effects were investigated in vivo. Firstly, BOT exhibited a strong action against E. coli lipopolysaccharide by improving intestinal integrity and regulating liver inflammatory and oxidative status, allowing better growth in challenged piglets. Secondly, during an ETEC challenge trial, BOT proved able to control ETEC virulence, thus enhancing intestinal integrity and inflammatory status, and allowing better growth patterns in infected piglets. Finally, in a clean feeding trial, BOT maintained good performance and considerably reduced medical treatments compared to ZnO.
In conclusion, BOT represents a novel feed additive to support growth and counteract stress in weaning piglets. By influencing several stages of the host-pathogen interaction, BOT represents a valid alternative to pharmacological ZnO
Translational relevance of liquid biopsy approaches in advanced melanoma
No full textof five patients treated with anti-PD-1 as first line treatment. Our results, although still exploratory, suggest the predictive potential of baseline testing of circulating miR-155-5p as biomarker of response to immunotherapy. With the aim of enhance melanoma CTCs detection we tested the feasibility of the microfluidic system EPISPOT in a DROP (EPIDROP). Using the EPIDROP assay, we developed a panel of markers specific for melanoma CTCs (MCAM, MCSP, MART-1). The 6 use of this panel could improve the identification of CTCs in melanoma patients, thus providing better prognostic information. Finally, we provided a comprehensive analysis of ccfDNA mutations in a metastatic patient who had an exceptional response to immunotherapy. We found several mutated genes associated with response to immunotherapy. In conclusion, we demonstrated the feasibility and usefulness of liquid biopsy in the personalized management of advanced melanoma patients who experience relapse and develop resistance to immunotherapy
Cardiogenesi diretta: nuove strategie molecolari per promuovere la rigenerazione cardiaca
No full textCertain species of the animal kingdom, such as zebrafish, possess the amazing capability of efficiently regenerating their damaged heart, through the proliferation of pre-existing cardiomyocytes. In contrast, mammals sharply lose this innate capacity during early postnatal development. Consequently, cardiomyocytes lost after injuries in adult mammals are not regenerated, potentially leading to impaired cardiac function and, in severe cases, heart failure. This study aimed to investigate whether the regulation of specific growth factors or hormones during postnatal mammalian development contributes to the loss of cardiomyocyte regenerative potential. Specifically, we identified growth factors with declining expression levels in early postnatal life in the mouse model and evaluated their mitogenic potential. Besides validating the pro-proliferative ability of previously identified regenerative growth factors, we unveiled novel factors stimulating cardiomyocyte cell cycle activity. Among them, BMP7, exhibited the most remarkable effects in triggering neonatal cardiomyocyte cell cycle activity, progression to the S-phase and division. Knockdown of Bmp7 in neonatal mouse cardiomyocytes in vitro and loss of function in zebrafish during cardiac regeneration in vivo reduced cardiomyocyte proliferation, suggesting that Bmp7 is crucial in the regenerative stages of mouse and zebrafish hearts. Conversely, bmp7 overexpression in zebrafish hearts or delivery at post-mitotic juvenile and adult mouse stages, in vitro and in vivo following myocardial infarction, boosted cardiomyocyte cycling. Mechanistically, we disclosed that BMPR1A/ACVR1 and ACVR2A/BMPR2 receptors and canonical SMAD5 and non-canonical ERK and AKT downstream signalling players mediate the BMP7 cardiomyocyte pro-regenerative effect.
In parallel, we unveiled the crucial role of glucocorticoids (GCs) in restraining cardiomyocyte proliferation through activation of the glucocorticoid receptor (GR). Antagonization of the GC-GR axis was sufficient to boost neonatal murine cardiomyocyte proliferation and adult cardiomyocyte regeneration after myocardial infarction. Collectively, our data support BMP7 administration or GC-GR axis antagonization as promising therapeutical strategies to enhance cardiac regeneration in mammals after injury
Italian public universities facing the challenge of European funds for scientific research: the importance of organizational dynamics
No full textThe current research project has a twofold objective: the first one to provide a descriptive analysis of the outputs and outcomes of EU Cohesion Policy and EU Funds devoted to scientific research in Italy and assess if and how the Italian universities have been able to fully (or to what extent) exploit this opportunity.
The second one is to evaluate if the organizational structure of the research offices of the universities - namely the type of decentralization used, the existence (or not) of specific internal policies and procedures, the quality of the human resources devoted to research offices etc. - have impacted upon the capacity of the Italian state universities to get more EU funds and to improve the management of already obtained funds.
Therefore, my research object stands at the crossroad of four strands of literature and scientific reports: those about Italian university, from both an historical and a public policy approach, those concerning the outputs of EU Funds (Research Funds and Structural Funds), those about business organization in higher education and research institutions, with a focus on governance of the universities, and those about public policies and their evaluation.
Little is known and little has been said in the literature about the factors that can facilitate or hinder the ability of Italian universities to obtain - and then spend profitably - European funds. The current research intends to fill this gap, paying particular attention to organizational features and mechanisms as inde-pendent variables.
The pioneering value of this research consists in the primary data collected, with a level of detail for funds and organizational aspects never achieved before.
The objective, as well as being explanatory, is also to give practical hints, and provide best practices, to the subjects directly involved in the implementation of research policies at university level
The international politics of digital development: a multi-method analysis of ICT infrastructure and policies in Africa
No full textDigital development is sometimes portrayed as a cure to poverty, a catalyst of socio-economic development, and an all-round solution to governance challenges. While intended to reduce the dependency of developing countries, it is striking that digital development is enabled by foreign-made infrastructure and devices, paid for by foreign aid and loans, and regulated by foreign-inspired norms and policies. Will digital development then aggravate or alleviate the global structural inequalities?
This thesis examines the international politics that drive and shape digital development in Sub-Saharan Africa. It adopts Susan Strange’s concept of structural power to situate digital development in the international political economy, where the interests of foreign and domestic actors lie. The empirical chapters zoom in on the role of China and Sino-African cooperation, Afro-European relations, and the implications for the agency of African states. Using both existing and originally collected data, the thesis triangulates the data in a multi-method analysis. A Qualitative Comparative Analysis demonstrates that development aid and loans underpin the Sino-African relations in the digital sector. Multivariate regression analysis shows that developing countries in Africa are more likely to adopt ICT policies compared to other regions of the Global South—a difference that the thesis ascribes to the historical and contemporary ties between African states and Europe. The geospatial analysis of foreign infrastructure providers and inflows of aid and loan presents a novel approach to classify the “degree” of agency of African states. A case study of Rwanda and Tanzania completes the analysis by shedding light on the challenges and opportunities of regional initiatives to enhance African agency.
Overall, the thesis finds that foreign actors engage in digital development abroad to pursue their own national interests. While their efforts contribute to digital development in African states, they also perpetuate Africa’s structural dependency on foreign infrastructure and finance