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Spatio-temporal variability of thermohaline properties and circulation of water masses along the Ross Ice Shelf
No full textThe Ross Ice Shelf (RIS) is Earth’s largest ice shelf. Located in the Ross Sea, Antarctica, it acts as a buttress to the Antarctic ice sheet, regulating the flow of inland glaciers. Its stability therefore exerts an indirect but crucial control on the potential contribution of Antarctic ice to global sea level rise. Although currently considered in a stable state, it may be subject to rapid disintegration. It is necessary to understand its long-term stability in a changing climate and its dynamics concerning interacting principal water masses, since its basal melting depends on the ocean circulation along the ice front and underneath the ice shelf. This study presents the most consistent and detailed multi‐decadal hydrographic time series along the RIS, spanning from 1995 to 2025, in terms of both spatial and temporal resolution. By integrating CTD profiles, LADCP measurements, and recent year-round autonomous Argo float data, we provide a comprehensive view of the spatio-temporal evolution of key water masses and their circulation. Analysis of the CTD record along the RIS front revealed significant long-term changes in High Salinity Shelf Water (HSSW), a precursor to Antarctic Bottom Water which contributes to the global thermohaline circulation. HSSW freshened between 1995 and 2011, followed by a salinity rebound that persisted through 2025. Ice Shelf Water (ISW), the coldest water mass in the world, which forms as HSSW interacts with the base of the ice shelf, mirrored these trends, indicating that changes in HSSW characteristics and formation directly influence the ISW properties beneath the RIS. We quantified interannual variability of Ocean Heat Content and summer-warmed, freshened Antarctic Surface Water (AASW) layer. Peak Ocean Heat Content values in 2012, linked to elevated surface temperatures and greater surface layer thickness, indicated that AASW may have delivered up to 4.7 ×10^19 J of heat toward the ice shelf base, highlighting its potential role in modulating basal melting. Moreover, an Optimum Multi Parameter mixing analysis was applied to the hydrographic data in order to understand the contribution of key water masses to the composition of the water column along the RIS, and how these contributions changed over time. LADCP data from six summer campaigns between 2006 and 2025 enabled estimates of cross-shelf heat fluxes and revealed also pathways of water mass transport towards the RIS cavity. Water mass circulation analysis confirmed known features, such as the westward flow of AASW, the ISW outflow in the central and eastern RIS sector, and the southward intrusion of HSSW near Ross Island. However, they also unveiled a greater complexity, including intermittent inflow-outflow behaviour, pointing to a more dynamic circulation regime along the RIS than previously assumed. Finally, observations from 13 Argo floats, deployed in key areas along the RIS front between 2020 to 2024, bridged a critical wintertime observational gap. This unique dataset directly captured the full year-round water column evolution, and particularly the HSSW formation in the RIS polynya during winter, a process previously only inferred. An observed AASW intrusion event beneath the RIS in 2021 allowed for the quantification of heat advected into the sub-ice shelf cavity (~1.8 × 10^19 J) and the estimation of a consequent localized basal melt rate of ~0.65 m yr−1. A warm layer of modified Circumpolar Deep Water (mCDW), characterized by its oceanic origin and elevated temperature and salinity, was observed during winter in the eastern Ross Sea in 2024, opening critical questions about its inflow pathways and its potential to drive basal melting if in direct contact with the RIS base and/or grounding line, challenging our current understanding of RIS stability. A focused analysis of the RIS polynya provided quantitative estimates of HSSW production rates for 2021 and 2022 (~0.22 and 0.43 Sv, respectively), derived from weekly Argo float salinity profiles and satellite-derived polynya extent. This production was found to be spatially constrained, with only specific sectors of the RIS polynya actively contributing to dense water production. Furthermore, the analysis directly linked polynya expansion to a specific wind regime, revealing that frequent, rather than strong, synoptic wind events are the primary driver of its efficiency and consequent dense water formation. These observations enhance our understanding of the variability in RIS water mass properties and provide a starting point for understanding the complex processes that govern RIS stability in a changing climate
"Think Follower, Think Female”: Need for Cognitive Closure, Followership, and the Mediation of Congruity between Follower Prototype and Gender Stereotypes
No full textGender inequalities toward women can threaten well-being in the workplace, reducing social inclusiveness. This empirical study addressed the causes of such disparities by considering the biased stereotypical association between women and followership and the individual’s epistemic motivation towards the stability of knowledge (i.e., need for cognitive closure; NCC). Based on the Role Congruity Theory and implicit theories of followership, a correlational study was conducted on a sample of male and female Italian workers recruited through direct social media platforms (N = 339; 51% women; Mage = 35.37, SDage = 11.37; 73.1% private sector workers; 26.9% public sector workers) to address the role of the NCC in endorsing the stereotyped association of women and followership. We hypothesised the NCC to be associated with evaluating women as better followers than men. We also expected the low incongruity between followership's prototype and gender bias, as expressed in terms of women's high communality, to mediate this effect. The results showed that individuals' high NCC led to higher ratings of women's efficacy as followers. The low incongruity between the follower prototype and gender biases mediated this effect. Besides highlighting the detrimental path leading to biased associations between women and subordinate positions in the workplace, a phenomenon that reduces equality in the workplace, this study can also inform on the strategies that might be implemented to increase inclusiveness and reduce social disparities toward women in the workplace
Identità, corpi e disforie: l’esperienza soggettiva e la valutazione della disforia di genere
No full textLa comprensione clinica e teorica della disforia di genere ha subito diverse trasformazioni, passando da una visione monodimensionale e centrata sul corpo a una prospettiva multidimensionale e contestuale. La presente ricerca di dottorato ha indagato l’esperienza soggettiva del genere e della disforia di genere nella popolazione transgender e non binaria italiana, attraverso un disegno articolato in tre studi. Il primo studio, di natura qualitativa, ha esplorato la costruzione dell’identità di genere in un campione di persone non binarie, mettendo in luce il ruolo del riconoscimento sociale, dei contesti relazionali e delle narrazioni culturali nello sviluppo dell’identità di genere. Il secondo studio ha indagato attraverso quattro focus group l’esperienza soggettiva della disforia di genere nelle sue dimensioni corporee e sociali, coinvolgendo un campione di uomini e donne trans e persone non binarie giovani adulte. Dallo studio è emersa una concettualizzazione multidimensionale e dinamica della disforia, che comprende il disagio corporeo, le dinamiche interpersonali e il minority stress. Il terzo studio ha operazionalizzato questo modello attraverso la costruzione e validazione della Body and Social Gender Dysphoria Scale (BSGDS), un nuovo strumento di misura della disforia di genere sviluppato secondo un approccio bottom-up e community-informed. La scala ha una struttura multifattoriale articolata in tre dimensioni distinte ma interconnesse: disforia corporea, disforia interpersonale e disforia socioculturale. Nel complesso, questa ricerca contribuisce alla definizione teorica ed empirica di un modello multidimensionale della disforia di genere, capace di riflettere in modo più fedele le forme in cui può essere esperita e di restituire voce a chi ne fa esperienza diretta
Design comparison of four-layer full-Nb3Sn and hybrid Nb3Sn/NbTi cos-theta dipoles for the CERN high field magnet R&D programme
No full textThe High Field Magnet (HFM) R&D programme at CERN aims to find technological solutions for the construction of accelerator magnets to be installed in future post-LHC colliders. The Italian Institute for Nuclear Physics (INFN) and CERN are collaborating to design and fabricate a new four-layer cos-theta dipole able to achieve a bore field of 14T with at least 20% margin on the load-line. Two design options are under evaluation: a four-layer dipole entirely made of Nb3Sn, and a hybrid configuration combining inner Nb3Sn layers with outer NbTi layers. Both options are being assessed for feasibility as short models, with scalable design choices for longer magnet prototypes suitable for accelerator integration. This paper presents a comparative study of the performance of the two design options. The results provide insights into the trade-offs between performance, complexity, and protection constraints in the development of next-generation high-field dipole magnets. The Full-Nb3Sn solution satisfies the HFM requirements, but the Hybrid solution is a promising, cost-effective alternative that can be considered for next-generation colliders
Enriching earth observation labeled data with quantum conditioned diffusion models
No full textThe rapid adoption of diffusion models (DMs) in the Earth Observation (EO) domain has unlocked new generative capabilities aimed at producing new samples, whose statistical properties closely match real imagery, for tasks such as synthesizing missing data, augmenting scarce labeled datasets, and improving image reconstruction. This is particularly relevant in EO, where labeled data are often costly to obtain and limited in availability. However, classical DMs still face significant computational limitations, requiring hundreds to thousands of inference steps, as well as difficulties in capturing the intricate spatial and spectral correlations characteristic of EO data. Recent research in Quantum Machine Learning (QML), including initial attempts of Quantum Generative Models, offers a fundamentally different approach to overcome these challenges. Motivated by these considerations, we introduce the Quanvolutional Conditioned U-Net (QCU-Net), a hybrid quantum–classical architecture that applies quantum operations within a conditioned diffusion framework using a novel quanvolutional feature-extraction approach, for generating synthetic labeled EO imagery. Extensive experiments on the EuroSAT RGB dataset demonstrate that our QCU-Net achieves superior results. Notably, it reduces the Fréchet Inception Distance by 64%, lowers the Kernel Inception Distance by 76%, and yields higher semantic accuracy. Ablation studies further reveal that strategically positioning quantum layers and employing entangling variational circuits enhance model performance and convergence. This work represents the first successful adaptation of class-conditioned quantum diffusion modeling in the EO domain, paving the way for quantum-enhanced remote sensing imagery synthesis
The key role of Pb-Bi, Pb-Te-Se and S-Fe-Te-Se inclusions, microstructures, and corrosion processes in reconstructing Etruscan metallurgy at Pyrgi (Latium, Italy)
No full textThe archaeological site of Pyrgi (Santa Severa, Rome, Italy) has yielded a diverse range of metal artifacts that provide valuable insights into the Etruscans' metallurgical knowledge and material selection practices. This study focuses on micro-inclusions, microstructure, chemical composition, and corrosive process of arrowheads, nails, and aes rude . Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), micro-Raman spectroscopy, and electrochemical analysis, i.e. , Voltammetry of Immobilized Particles (VIMP), and Mott-Schottky (MS) were used. The nails and aes rude are pure copper, with minor contents of tin and lead, while the arrowheads are ternary bronze alloy (Cu-Sn-Pb). The microstructures of nails and aes rude are characterized by the presence of Pb-Bi, Pb-Te-Se, and S-Te-Se-Fe micro-inclusions within the metal matrix, which provide insights into smelting processes, the nature of the ores used, and technological capabilities. The variability of inclusions suggests the use of polymetallic minerals as starting materials. Tellurium and selenium suggest refining practices and smelting techniques that were not fully optimized. The corrosion patinas are composed of cuprite, malachite, and trihydroxychlorides. The Mott-Schottky analysis highlighted variations in the electrochemical response of the corrosion layers, suggesting different alteration conditions among areas of Pyrgi. These results contribute to the exploration of Etruscan metallurgical choices and techniques, highlighting variations in smelting processes, raw materials, and processing practices
Diagnostic Performance of a DOAC Urine Dipstick in Obese Outpatients with Atrial Fibrillation: Comparison with Plasma Concentrations
No full text: Background: atrial fibrillation (AF) patients with obesity and high thromboembolic risk need oral anticoagulant therapy. Limited data are available on direct oral anticoagulants (DOACs) in this population, and a point-of-care method has been validated to support rapid clinical decisions and to identify on-off plasma concentration thresholds. Methods: This is a monocentric, cross-sectional diagnostic accuracy study on obese AF outpatients referred to Policlinico Umberto I of Rome. Urinary Dipsticks were assessed with separate pads for factor Xa (FXA-i) and thrombin inhibitor (THR-i) and compared to the reference standard of trough and peak plasma concentrations with chromogenic assays/dTT and prespecified plasma thresholds for each DOAC. Study endpoints were the sensitivity, specificity, positive and negative predictive values (PPV and NPV) of DOACs Dipstick compared to plasma concentrations. Sub-analyses according to obesity severity and type of DOAC were performed. Results: 320 paired plasma and urine samples were available from 160 enrolled patients (mean age 73.2 ± 9.1 years). Compared to trough plasma concentrations, DOACs Dipstick showed a sensitivity of 99.24% (mean, 95% confidence interval, CI 95.82-99.98), specificity of 6.89% (0.85-22.76), PPV 82.80% (81.32-84.18), NPV 66.67% (15.79-95.52). On the other hand, compared to peak plasma concentrations, DOACs Dipstick showed a sensitivity of 97.8% (93.7-99.5), specificity of 0% (0.0-15.4), and PPV of 85.9% (85.6-86.2). Urinary Dipstick showed a sensitivity of 99.10% (95.4-100.0), specificity of 4.70% (0.60-16.20) and a PPV and NPV of 74.50% (73.2-75.8) and 66.70 (15.7-95.6), compared to plasma thresholds > 30 ng/mL of FXA-I and THR-I. Sub-analyses showed similar results between FXA-i and THR-i. Conclusions: The urine point-of-care has high sensitivity, acceptable PPV, but low specificity and NPV in AF obese patients and may be useful only in selected clinical scenarios
Analysis of office and out-of-office blood pressure levels in adult outpatients with hypertensive urgency: a cross-sectional, retrospective study in a hypertension excellence center
No full textIntroduction: Hypertensive urgency (HU) is a clinical condition characterized by rapid office blood pressure (BP) elevation in the absence of hypertension-mediated organ damage (HMOD). Aim: To evaluate out-of-office BP levels and predictors of HU in adult outpatients with stage 3 hypertension. Methods: We included patients who were consecutively referred for office and out-of-office BP assessment. All patients underwent BP measurements using a validated, oscillometric device (Mobil-O-Graph PWA Monitor, I.E.M. GmbH, Stolberg, Germany). Patients were stratified into two groups: grade 3 hypertension (either systolic BP ≥180 mmHg or diastolic BP ≥110 mmHg); HU (both systolic BP ≥180 and diastolic BP ≥110 mmHg). Results: We identified 828 adult outpatients (42.6% women, age 56.5 ± 13.6 years, BMI 27.5 ± 5.2 kg/m2, 55.2% on therapy), among whom 655 (79.1%) had grade 3 hypertension and 173 (20.9%) had HU. HU patients consistently showed significantly higher home (157.0 ± 25.3 vs. 146.9 ± 20.4 mmHg), 24-h (155.6 ± 18.3 vs. 143.2 ± 13.7 mmHg), daytime (160.5 ± 18.2 vs. 147.7 ± 13.9 mmHg), and night-time (143.2 ± 20.1 vs. 131.0 ± 16.1 mmHg) systolic BP values than those with stage 3 hypertension, even when treated. Diastolic BP levels were also higher at all BP measurements. Female sex [odds ratio (OR) 0.53 (95% confidence interval (CI) 0.32-0.86); P = 0.010], age >50 years [OR 2.57 (95% CI 1.48-4.69); P = 0.001], smoking [2.03 (1.21-3.37); P = 0.006], home diastolic [OR 1.02 (95% CI 1.00-1.04); P = 0.013] and daytime systolic [OR 1.04 (95% CI 1.03-1.06); P < 0.001] BP were independent predictors of having HU at multivariate analysis. Conclusions: HU outpatients showed persistently higher out-of-office BP levels than those with stage 3 hypertension, even when treated
A note on the distribution of risk functions for estimation in scale-exponential families
No full textIn parametric statistical decision theory, the performance of a decision function is evaluated in terms of its risk function, a quantity that depends on the parameter of the model. The risk function is typically summarized by the Bayes risk, its expected value with respect to a prior distribution assigned to the parameter. However, the study of the whole distribution of the risk function and the derivation of additional summaries (such as quantiles and the mode) may provide a better insight into the overall risk associated to the decision. In this article we consider models that are scale-exponential families. In the case of point or interval estimation we provide general closed-form expressions for cumulative distribution and density functions of the random risk along with some relevant summaries. We show how this unifying approach can be specialized to specific relevant models and also employed for the definition of sample size determination criteria
Genomic approach for the identification of resistance mechanisms to new antibiotics and inhibitors of resistance mechanisms in clinically relevant Gram-negative bacteria
No full textIn the last decades, genomics has revolutionized microbiology through advances in sequencing technologies and computational tools, enabling vast bacterial genome analyses. These developments have deepened understanding of bacterial evolution, diversity, and molecular basis of antimicrobial resistance.
Over the past three years, this PhD project explored how Klebsiella pneumoniae rapidly evolves under antibiotic pressure, leveraging advances in whole-genome sequencing and bioinformatics to uncover the genetic basis of antimicrobial resistance. Whole-genome sequencing has been used in the different projects, based on clinical isolates obtained by the Policlinico Umberto I of Rome, Italy, as a key method for identifying resistance mechanisms known and novel to perform comparative genomics, and trace resistance evolution along the years in high-risk clones of K. pneumoniae.
Early investigations revisited K. pneumoniae sequence type (ST) 37 isolates, initially detected in 2006 and thought to have disappeared after 2010. Genomic analysis of new ceftazidime-avibactam (CZA)-resistant ST37 isolates revealed their close relation to historical strains, suggesting long-term persistence in the hospital environment and re-emergence under selective antibiotic pressure. Subsequent studies focused on K. pneumoniae ST307, a globally disseminated high-risk clone. Genomic and plasmid analyses of CZA- and carbapenem-resistant strains revealed complex plasmid rearrangements and recombination events that explained diverse resistance profiles, demonstrating the remarkable genetic plasticity of ST307. A clinical case involving ST512 highlighted in vivo evolution of resistance during prolonged antimicrobial therapy, including plasmid loss, porin mutations, and a cirA nonsense mutation conferring cefiderocol resistance. Further work identified a novel mechanism of cefiderocol resistance involving interaction between two plasmids pKpQIL (carrying blaKPC variants) and pKPN (harboring the ferric citrate fec system) which was shown to reduce drug susceptibility in both E. coli and K. pneumoniae. In the final phase, a CRISPR-Cas9 conjugative system was engineered to selectively eliminate plasmid-borne blaKPC genes. Overall, the research of this thesis highlights how K. pneumoniae adapts rapidly to new antibiotics, with sequence type-specific trajectories shaped by plasmid dynamics and their acquisition of antimicrobial resistance determinants