10081 research outputs found
Sort by
Embedded representations of social interactions
Get PDFSocial interactions have been the focus of social science research for a century, but their study has recently been revolutionized by novel data sources and by methods from computer science, network science, and complex systems science. The study of social interactions is crucial for understanding complex societal behaviours. Social interactions are naturally represented as networks, which have emerged as a unifying mathematical language to understand structural and dynamical aspects of socio-technical systems. Networks are, however, highly dimensional objects, especially when considering the scales of real-world systems and the need to model the temporal dimension. Hence the study of empirical data from social systems is challenging both from a conceptual and a computational standpoint. A possible approach to tackling such a challenge is to use dimensionality reduction techniques that represent network entities in a low-dimensional feature space, preserving some desired properties of the original data. Low-dimensional vector space representations, also known as network embeddings, have been extensively studied, also as a way to feed network data to machine learning algorithms. Network embeddings were initially developed for static networks and then extended to incorporate temporal network data. We focus on dimensionality reduction techniques for time-resolved social interaction data modelled as temporal networks. We introduce a novel embedding technique that models the temporal and structural similarities of events rather than nodes. Using empirical data on social interactions, we show that this representation captures information relevant for the study of dynamical processes unfolding over the network, such as epidemic spreading. We then turn to another large-scale dataset on social interactions: a popular Web-based crowdfunding platform. We show that tensor-based representations of the data and dimensionality reduction techniques such as tensor factorization allow us to uncover the structural and temporal aspects of the system and to relate them to geographic and temporal activity patterns
Metal additive manufacturing of soft magnetic material for electric machines
Get PDFThis research work concerns the application of additive manufacturing (AM) technologies in new electric mobility sectors. The unmatched freedom that AM offers can potentially change the way electric motors are designed and manufactured. The thesis investigates the possibility of creating optimized electric machines that exploit AM technologies, with potential in various industrial sectors, including automotive and aerospace. In particular, we will evaluate how the design of electric motors can be improved by producing the rotor core using Laser Powder Bed Fusion (LPBF) and how the resulting design choices affect component performance. First, the metallurgical and soft magnetic properties of the pure iron and silicon iron alloy parts (Fe-3% wt.Si) produced by LPBF will be defined and discussed, considering the process parameters and the type of heat treatment. This research shows that using LPBF, both pure iron and iron silicon, the parts have mechanical and magnetic properties different from the laminated ones. Hence, FEM-based modeling will be employed to design the rotor core of an SYN RM machine to minimize torque ripple while maintaining structural integrity. Finally, we suggest that further research should extend the field of applicability to other electrical devices
The mesophotic zone of the Mediterranean Sea: spatial definition, biodiversity, and predictive models
Get PDFThe mesophotic zone is frequently defined as ranging between 30-40 and 150 m depth. However, these borders are necessarily imprecise due to variations in the penetration of light along the water column related to local factors. Moreover, density of data on mesophotic ecosystems vary along geographical distance, with temperate latitudes largely less explored than tropical situations. This is the case of the Mediterranean Sea, where information on mesophotic ecosystems is largely lower with respect to tropical situations.
The lack of a clear definition of the borders of the mesophotic zone may represent a problem when information must be transferred to the policy that requires a coherent spatial definition to plan proper management and conservation measures.
The present thesis aims at providing information on the spatial definition of the mesophotic zone in the Mediterranean Sea, its biodiversity and distribution of its ecosystems.
The first chapter analyzes information on mesophotic ecosystems in the Mediterranean Sea to identify gaps in the literature and map the mesophotic zone in the Mediterranean Sea using light penetration estimated from satellite data.
In the second chapter, different visual techniques to study mesophotic ecosystems are compared to identify the best analytical method to estimate diversity and habitat extension.
In the third chapter, a set of Remotely Operated vehicles (ROV) surveys performed on mesophotic assemblages in the Mediterranean Sea are analyzed to describe their taxonomic and functional diversity and environmental factors influencing their structure.
A Habitat Suitability Model is run in the fourth chapter to map the distribution of areas suitable for the presence of deep-water oyster reefs in the Adriatic-Ionian area.
The fifth chapter explores the mesophotic zone in the northern Gulf of Mexico providing its spatial and vertical extension of the mesophotic zone and information on the diversity associated with mesophotic ecosystems
"Roman tradition" and general principles of law: The Italian debate between the 19th and 20th centuries
Get PDFIl presente lavoro verte sul ruolo svolto dal diritto romano e – più in generale – dalla “tradizione romanistica” all'interno del sistema giuridico nazionale posteriore alla codificazione civile del 1865. L'attenzione è rivolta principalmente all'art. 3 delle Disposizioni preliminari del Codice del 1865 con il suo riferimento ai 'principi generali del diritto' e, dunque, all'analogia iuris. La prima parte dello studio si concentra sull'analisi di alcune voci della scienza giuridica italiana tra Otto e Novecento, nei loro diversi approcci – laddove riscontrabili – rispetto allo studio e al recupero (in chiave moderna) del diritto romano.
La seconda parte è invece dedicata all'esame della prassi giudiziaria e, più specificamente, delle Corti di Cassazione. In questa fase si persegue un duplice obiettivo: da un lato, verificare se, ed eventualmente in che misura, il diritto romano possa ancora svolgere un ruolo nella (moderna) giurisprudenza di legittimità; dall'altro, valutare la concreta possibilità, prospettata da una parte della scienza giuridica, di ricorrere in Cassazione per impugnare una sentenza asseritamente contraria ai principi generali del diritto sanciti dall'art. 3 co. 2 delle Preleggi.
L'analisi prende dunque le mosse dal contenuto delle singole decisioni della Cassazione, per poi passare all'esegesi dei frammenti di volta in volta richiamati; infine, si concluderà con un'operazione di sintesi volta a valutare, per ciascun caso, la coerenza (giuridica) del ragionamento analogico.The research deals with some aspects of the reuse of Roman sources, and of their modern tradition, within the national legal system after the civil codification. The attention is directed mainly to art. 3, Preliminary provisions of the Code of 1865 with its reference to the ‘general principles of law’ in order to the analogia iuris. Based on this research approach, the study focuses on the analysis of some specific voices of Italian legal science from both nineteenth and twentieth centuries.
The second part of the study is devoted to an examination of judicial practice and, more specifically, of the Supreme Courts. At this stage we pursue a twofold objective: on the one hand, to ascertain whether, and if so to what extent, Roman law could still play a role in the (modern) jurisprudence of legitimacy; on the other hand, to assess the concrete possibility, envisaged by a part of legal science, of appealing to the Supreme Court to challenge a judgment allegedly contrary to the general principles of law laid down in Art. 3 par. 2 of the Prelaws.
The analysis thus starts from the content of the individual decisions of the Supreme Court, then moves on to the exegesis of the fragments referred to each time; finally, we will conclude with a summary operation aimed at assessing, for each case, the (legal) consistency of the analogical reasoning
Essays in Gender Economics
Get PDFThis thesis consists of three papers on gender economics. Chapter 1 studies whether people dislike collaborating with someone who corrects them and whether the dislike is stronger when that person is a woman. Having a good relationship with colleagues is integral in group work, potentially leading to successful collaborations. However, there are occasions when people have to correct their colleagues. Using a quasi-laboratory experiment, I find that people, including those with high productivity, are less willing to collaborate with a person who has corrected them even if the correction improves group performance. In addition, I find suggestive evidence that men respond more negatively to women’s corrections, which is not driven by their beliefs about the difference in women’s and men’s abilities. These findings suggest that there is a behavioral bias in group work that distorts the optimal selection of talents and penalizes those who correct others’ mistakes, and the distortion may be stronger when women correct men. Chapter 2 studies the role of gender and cognitive skills on other peoples’ generosity. Using a novel experimental design where I exogenously vary gender and cognitive skills and sufficiently powered analysis, I find neither the two attributes nor their interactions affect other people’s generosity; if anything, people are more generous to women with high potential. Chapter 3 studies how increased legal tolerance toward domestic violence affects married women’s welfare using the domestic violence decriminalization bill introduced to the Russian national congress in 2016. Using difference-in-differences and flexibly controlling for macroeconomic shocks, I find that the bill decreased married women’s life satisfaction and increased depression, especially among those with a college degree and a highly qualified white-collar occupation supposed to be more sensitive to gender regressive atmosphere. Consistent with this conjecture, people became more tolerant toward general and domestic violence after the bill
Molecular analysis of Papillomavirus-induced cutaneous tumors in equids
Get PDFPapillomavirus associated tumors are well recognized entities in humans as well as in animals. Here is reviewed the current understanding of human papillomavirus (HPV) associated cancers to better understand the oncogenic mechanisms of Equine papillomavirus (EcPV) and Bovine Papillomavirus (BPV) in horses.
In the first part of this study the interactions between Equine papillomavirus 2 (EcPV-2) and cell cycle proteins are discussed. EcPV-2 has been recognized as the cause of genital squamous cell carcinomas (SCCs) in horses, but the exact mechanism of carcinogenesis is not fully understood. The aim of the first part of this study is to assess the expression of cell cycle proteins p53, p16, pRB and Cyclin D1 in a series of equine SCCs and papillomas.
Results confirm the role of EcPV-2 in the pathogenesis of genital SCCs. Moreover, in a small subset of ocular SCCs, EcPV-2 was detected for the first time. By immunohistochemistry, p53 was mostly expressed in ocular SCCs with a suprabasal localization. Regarding p16, overexpression was associated with increased mitotic index but not with viral infection. Investigation on pRB and Cyclin D1 proteins did not show significant correlation with other variables.
The second part of this study is focused on the carcinogenetic mechanisms of BPV in equine sarcoids. The aim of the second part of this study was to characterize the typical histomorphological features of equine sarcoids, assess the expression of cell cycle proteins and Ki-67 proliferation index.
Our results confirm that the typical histological features of sarcoids cannot be used to correctly classify the clinical types. Moreover, in a subset of sarcoids low pRB-Cyclin D1 scores were associated with simultaneous high p16 expression. The Ki-67 proliferation index confirm the low proliferative activity of sarcoids, except for tumors displaying a fascicular pattern. Finally, a subset of sarcoids recurred after excision
Identification of a molecular signature as potential biomarker in blood of symptomatic and asymptomatic patients with carotid atherosclerosis
Get PDFBackground and Objectives: Carotid revascularization to prevent future vascular events is reasonable in patients with high-grade carotid stenosis. Currently, several biomarkers to predict carotid plaque development and progression have been investigated, among which microRNAs (miRs) are promising tools for the diagnosis of atherosclerosis.
Methods and Results: A total of 49 participants were included in the study, divided into two main populations: Population 1 comprising symptomatic and asymptomatic inpatients, and Population 2 comprising asymptomatic outpatients.
The study consisted of two main phases: a preliminary discovery phase and a validation phase, applying different techniques. MiR-profiles were performed on plasma and plaque tissue samples obtained from 4 symptomatic and 4 asymptomatic inpatients. MiRs emerging from profiling comparisons, i.e. miR-126-5p, miR-134-5p, miR-145-5p, miR-151a-5p, miR-34b, miR-451a, miR-720 and miR-1271-5p, were subjected to validation through RT-qPCR analysis in the total cohort of donors. Comparing asymptomatic and symptomatic inpatients, significant differences were reported in the expression levels of c-miRs for miR-126-5p and miR-1271-5p in blood, being more expressed in symptomatic subjects. In contrast, simultaneous evaluation of the selected miRs in plaque tissue samples did not confirm data obtained by the miR profiling, and no significant differences were observed. Using Receiver-Operating Characteristic (ROC) analysis, a circulating molecular signature (mir-126-5p, miR-1271-5p, albumin, C-reactive protein, and monocytes) was identified, allowing the distinction of the two groups in Population 1 (AUC = 0.795).
Conclusions: Data emerging from this thesis suggest that c-miRs (i.e. miR-126-5p, miR-1271-5p) combined with selected haemato-biochemical parameters (albumin, C-reactive protein, and monocytes) produced a good molecular 'signature' to distinguish asymptomatic and symptomatic inpatients. C-miRs in blood do not necessarily reflect the expression levels of the same miRs in carotid plaque tissues since different mechanism can influence their expression
Understanding, defining and assessing food systems’ social and economic sustainability indicators: implementation of mixed methodologies for policy insights
Get PDFSustainability encompasses the presence of three dimensions that must coexist simultaneously, namely the environmental, social, and economic ones. The economic and social dimensions are gaining the spotlight in recent years, especially within food systems. To assess social and economic impacts, indicators and tools play a fundamental role in contributing to the achievements of sustainability targets, although few of them have deepen the focus on social and economic impacts. Moreover, in a framework of citizen science and bottom-up approach for improving food systems, citizen play a key role in defying their priorities in terms of social and economic interventions. This research expands the knowledge of social and economic sustainability indicators within the food systems for robust policy insights and interventions. This work accomplishes the following objectives: 1) to define social and economic indicators within the supply chain with a stakeholder perspective, 2) to test social and economic sustainability indicators for future food systems engaging young generations. The first objective was accomplished through the development of a systematic literature review of 34 social sustainability tools, based on five food supply chain stages, namely production, processing, wholesale, retail, and consumer considering farmers, workers, consumers, and society as stakeholders. The second objective was achieved by defining and testing new food systems social and economic sustainability indicators through youth engagement for informed and robust policy insights, to provide policymakers suggestions that would incorporate young generations ones. Future food systems scenarios were evaluated by youth through focus groups, whose results were analyzed through NVivo and then through a survey with a wider platform. Conclusion addressed the main areas of policy interventions in terms of social and economic aspects of sustainable food systems youth pointed out as in need of interventions, spanning from food labelling reporting sustainable origins to better access to online food services
Flexible Computing Systems For AI Acceleration At The Extreme Edge Of The IoT
Get PDFEmbedding intelligence in extreme edge devices allows distilling raw data acquired
from sensors into actionable information, directly on IoT end-nodes. This computing
paradigm, in which end-nodes no longer depend entirely on the Cloud, offers undeniable
benefits, driving a large research area (TinyML) to deploy leading Machine Learning
(ML) algorithms on micro-controller class of devices. To fit the limited memory storage capability of these tiny platforms, full-precision Deep Neural Networks (DNNs) are compressed by representing their data down to byte and sub-byte formats, in the integer domain. However, the current generation of micro-controller systems can barely cope with the computing requirements of QNNs. This thesis tackles the challenge from many perspectives, presenting solutions both at software and hardware levels, exploiting parallelism, heterogeneity and software programmability to guarantee high flexibility and high energy-performance proportionality. The first contribution, PULP-NN, is an optimized software computing library for QNN inference on parallel ultra-low-power (PULP) clusters of RISC-V processors, showing one order of magnitude improvements in performance and energy efficiency, compared to current State-of-the-Art (SoA) STM32 micro-controller systems (MCUs) based on ARM Cortex-M cores. The second contribution is XpulpNN, a set of RISC-V domain specific instruction set architecture (ISA) extensions to deal with sub-byte integer arithmetic computation. The solution, including the ISA extensions and the micro-architecture to support them, achieves energy efficiency comparable with dedicated DNN accelerators and surpasses the efficiency of SoA ARM Cortex-M based MCUs, such as the low-end STM32M4 and the high-end STM32H7 devices, by up to three orders of magnitude. To overcome the Von Neumann bottleneck while guaranteeing the highest flexibility, the final contribution integrates an Analog In-Memory Computing accelerator into the PULP cluster, creating a fully programmable heterogeneous fabric that demonstrates end-to-end inference capabilities of SoA MobileNetV2 models, showing two orders of magnitude performance improvements over current SoA analog/digital solutions
Advanced Organic Materials: from Additive Manufacturing to Organic Electronics and Biomedical Applications
Get PDFThis manuscript represents an overview on the studies I was involved in during my PhD at the Industrial Chemistry Department “Toso Montanari”, in the ASOM (Advanced Smart Organic Materials) research group under the supervision of Prof. Letizia Sambri and Prof. Mauro Comes Franchini. Those research have been focused on the development of organic materials for advanced applications in different fields, among which organic electronics, additive manufacturing (3D Printing) and biomedical applications can be underlined