Archivio istituzionale della ricerca - Alma Mater Studiorum Università di Bologna
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Radical Autobiography as Place Storytelling: The Troubled Antiracist Geopoetics of “Wild Bill”
No full textThis paper explores a neglected aspect of the otherwise widely studied life and thought of radical geographer William Wheeler “Wild Bill” Bunge (1928-2013). That is, his engagement with the kind of narrative storytelling that is studied today under labels such as “geopoetics” and “geo-literature”. It makes so starting by an unexpected archival discovery: a 478-page document, titled Donia’s Garden (hereafter DG), dedicated to Bunge’s second wife Donia Johnson and containing the messy draft of what Bunge tried unsuccessfully to publish as a book. This work was presented by its author as nothing less than the new “Anne Frank’s Diary”, and the only copy that I could locate hitherto survives in the archives of Bunge’s friend and correspondent Anne Buttimer (1938-2017). Comparing this intriguing document, which performs an (auto)biography of Bunge and his family from 1971 to the early 1990s, with other Bunge’s works such as Fitzgerald (1971) of which DG was a sort of continuation, I argue that Bunge’s kind of radical autobiography and storytelling provides insights to both antiracist geopoetics and the biographical turn in Geography, highlighting the complex, unpredictable and often contradictory relations between life, networks and ideas. Without undermining the groundbreaking contributions that Bunge gave to “canonised” Geography, this paper shows that his writing was also a literary genre—a wild one, like the author
A GARCH model with two volatility components and two driving factors
No full textWe introduce a novel GARCH model that integrates two sources of uncertainty to better capture the rich, multi-component dynamics often observed in the volatility of financial assets. This model provides a quasi closed-form representation of the characteristic function for future log-returns, from which semi-analytical formulas for option pricing can be derived. A theoretical analysis is conducted to establish sufficient conditions for strict stationarity and geometric ergodicity, while also obtaining the continuous-time diffusion limit of the model. Empirical evaluations, conducted both in-sample and out-of-sample using S&P500 time series data, show that our model outperforms widely used single-factor models in predicting returns and option prices. The code for estimating the model, as well as for computing option prices, is made accessible in MATLAB language.
A comparative study of OPC, WPC, and LC3 cements by low-field 1H TD NMR
No full textLimestone Calcined Clay Cement (LC3) is a promising alternative to Ordinary Portland Cement (OPC); however, its characterization using Time-Domain Nuclear Magnetic Resonance (1H TD NMR) remains underexplored, leaving important aspects insufficiently investigated. In this study, we analyzed OPC, White Portland Cement (WPC), and LC3 pastes at specific hydration times using a portable NMR MOUSE, which can be used in situ, and a wide-bore permanent magnet NMR for synchronized tests.
Our results revealed a consistent decrease in the overall signal during hydration for both T1 (longitudinal or spin-lattice) relaxation time and T2 (transverse or spin-spin) relaxation time. The T1/T2 ratio, obtained assuming a monomodal relaxation time distribution, showed the LC3 > OPC > WPC trend for both NMR MOUSE and permanent magnet measurements, as well as dependence on the binder type and iron content.
With T1-T2 correlation 2D maps, we followed two spin populations present in the samples, assigned to interlayer water and gel pores, which exhibited distinct T1/T2 ratios.
We investigated the influence of iron content on relaxation times, and the component with short relaxation time (interlayer water) did not exhibit a dependence on iron content.
This study provides the first detailed 1H TD NMR investigation of LC3 hydration, analyzing T1, T2, and T1/ T2 in comparison with WPC and OPC. It reveals the evolution of relaxation times with hydration and iron content and complements previous T2-focused studies by incorporating T1 to offer deeper insight into hydration mechanisms
Unique-Solution of Equations in Higher-Order Process Calculi with Passivation
No full textStefani and coauthors, in various papers, have advocated the usefulness of constructs for localities and passivation in higher-order process languages. They have also shown that the constructs may have surprising consequences on the theory of the languages. In this paper, dedicated to Jean-Bernard Stefani, we show that, in contrast, proof techniques based on unique-solution of equations are robust enough to bear the presence of such constructs
On mean field games in infinite dimension
No full textWe study a Mean Field Games (MFG) system in a real, separable infinite dimensional Hilbert space. The system consists of a second order parabolic type equation, called Hamilton-Jacobi-Bellman (HJB) equation in the paper, coupled with a nonlinear Fokker-Planck (FP) equation. Both equations contain a Kolmogorov operator. Solutions to the HJB equation are interpreted in the mild solution sense and solutions to the FP equation are interpreted in an appropriate weak sense. We prove well-posedness of the considered MFG system under certain conditions. The existence of a solution to the MFG system is proved using Tikhonov's fixed point theorem in a proper space. Uniqueness of solutions is obtained under typical separability and Lasry-Lions type monotonicity conditions
The Modern and Ancient Central-Mediterranean Gateways
No full textGateways, seaways and straits are physical elements of sedimentary basins that are hierarchically distinguished based on their dimensions and temporal persistence. The term ‘gateway’ applies to any oceanographic or marine connection, regardless of its size (width and length), duration and depth (shallow v. deep water). Seaways are broad marine passages, spanning from hundreds to thousands of kilometres in width, and active in the range from hundreds of years to tens of kiloyears in geological time. Straits are narrower passageways, connecting sub-basins within larger marine areas, persisting for no longer than 10 kyr and producing distinct sedimentary records as individual depositional systems. In this paper, we focus on the Modern Central-Mediterranean Gateway, now represented by the coalescent Strait of Sicily, the Egadi Islands and the Messina Strait. These connections, linking the western with the eastern Mediterranean sub-basins, drive continuous tidally modulated water exchange and sediment transport, representing an example of a modern gateway. We then provide field-based examples of the sedimentary record of the former gateway, referred to as the Ancient Central-Mediterranean Gateway, here represented by four major straits that developed during the Pliocene epoch and Quaternary period along localized graben dissecting the southernmost edge of the Italian peninsula. We discuss the geological features of each of these straits, along with their depositional architectures and facies. These elements record the initiation of specific depositional processes, possibly enhanced by a stronger penetration of the Atlantic water inflow from the Gibraltar Strait, reinforced by the onset of the Northern Hemisphere glaciation
Automating Ergonomics: Scalable AI for Technical Hand Grip Classification
No full textRecent studies show that most Work-Related Musculoskeletal Disorders (WMSDs) of the hand and wrist are the result of repeated stresses, caused by repetitive activities over a long time. Tools like ergonomics risk indexes, have been developed to assess upper limb overload in repetitive tasks: part of this evaluation is based on the observation of the number and frequency of Technical Hand Grips (THGs), differing by the number of fingers involved, the exerted forces and most affected regions. Ergonomists typically assess THGs manually via video review, which is time-consuming: a need arises for the automation of these procedures. The rapid and functional creation of AI models capable of classifying efficiently THGs presents some particular challenges: (1) labeling a huge amount of images at ergonomist-level, since, to the best of our knowledge, there are no useful datasets available; (2) considering object occlusions as an intrinsic requirement of realistic study of THGs; (3) moving towards the shared request of data anonymization. This work proposes an Active Learning system in which an initial model labels THGs from videos and consults an Oracle (ergonomist) only when uncertain. An implemented AI (GNN) model is trained on these carefully labeled data to replace the first rudimentary model. The process repeats until the desired model accuracy or data set size is reached. This has guaranteed: (1) a rapid labeling strategy and scaling of the THGs classification model that learns from selected “good” data; (2) implement an occlusion-robust model, by applying selective masking strategies; (3) anonymization through graph-structured data
Endometrial carcinoma and immune escape: prognostic relevance of HLA class I loss in NSMP subtype
No full textAims: This study aims to define and characterize human leukocyte antigen class I (HLA-I) expression in a consecutive series of molecularly classified endometrial carcinomas (ECs), and to evaluate its association with clinicopathologic features, spatial cancer–immune phenotypes and patient prognosis, with a focus on the NSMP (no specific molecular profile) subtype. Methods and results: HLA-I expression was assessed by immunohistochemistry on whole tissue sections from 208 ECs, classified into POLE-mutated, MMR-deficient (MMRd), p53-abnormal (p53abn) and NSMP subtypes. Loss of HLA-I was identified in 31% of cases and was associated with adverse features including high-grade, aggressive histotypes, deep myometrial invasion, substantial lymphovascular space invasion (LVSI), extensive tumour necrosis and an ‘excluded’ immune phenotype. While HLA-I loss showed no significant prognostic impact in POLE, MMRd or p53abn tumours, it significantly correlated with worse disease-free survival in NSMP tumours (P < 0.001). Multivariate analysis confirmed HLA-I loss as an independent prognostic factor in early-stage NSMP ECs, in addition to substantial LVSI, presence of lymph node metastases and spatial cancer–immune phenotypes. Integration of HLA-I status improved the performance of predictive models over time. Conclusions: HLA-I loss defines a biologically aggressive subgroup within NSMP ECs and is associated with adverse clinicopathologic and immune features. Assessment of HLA-I expression could refine risk stratification in NSMP ECs, a group traditionally lacking robust prognostic markers and may help identify patients who could benefit from intensified clinical surveillance and future immunomodulatory treatment strategies
Wall roughness and viscous dissipation effects in microchannel heat sinks with semicircular cross-section
No full textA statistical analysis of the wall roughness effect is carried out to determine the impact of the shape uncertainty on the Poiseuille number and Nusselt number of laminar forced convection. The focus is on the fully developed regime in a semicircular microchannel where the heat transfer occurs from the diametrical plane boundary, modelled as a perfectly smooth surface. On the other hand, the curved semicircular boundary is devised as rough and with a negligible wall heat flux. Three types of thermal boundary conditions are implemented: the T condition, the H1 condition and the H2 condition. The T condition serves to model a case where the fluid temperature does not undergo any change in the streamwise direction, while the H1 and H2 conditions are employed to describe a net heating of the fluid. A statistical sample of several different rough microchannels is used to detect the actual effects of roughness on the Poiseuille number and on the Nusselt number, through the evaluation of their average values and standard deviations. The governing local momentum and energy balance equations are solved numerically by a finite element method taking into account the viscous dissipation contribution to the local energy balance
Investors Attention in Financial Markets
No full textInvestors have access to thousands of stocks listed globally, making the search for individual stocks both challenging and time-consuming. How do investors choose which stocks to invest in, given the vast array of options? This chapter explores the dynamics of investor attention, which is a critical precursor to investment decisions. We also provide evidence on investor attention using Apple Inc. as a prominent example