513225 research outputs found
Sort by
Gravitational wave signatures of scalarized black holes and horizonless compact objects
No full textBlack holes are among the simplest objects in the universe, yet they serve as one of the most powerful testbeds for probing some of the deepest puzzles in physics, such as the curvature singularity, the information loss paradox and other fundamental challenges within general relativity. These unresolved issues motivated the investigation of alternative models of compact objects. Among the various proposals, the Fuzzball program stands out as one of the most promising top-down approaches to resolving these problems in one coherent picture, as it describes the black hole as an ensemble of smooth and horizonless geometries representing its microstates with the same mass and charge.
The flourishing field of gravitational waves research provides an excellent avenue for investigating the phenomenology of these objects. This thesis focuses on the study of toy models whose simplified yet physically motivated solutions, involving gravity coupled with additional degrees of freedom, effectively capture key properties of Fuzzballs. We investigate the perturbative response of these objects by computing their oscillatory modes and highlighting the presence of echo patterns in the ringdown signal. Moreover, we analyze extreme-mass-ratio inspirals as a promising probe to differentiate classical black holes from horizonless compact objects in these toy models
Automated lung texture analysis for assessing interstitial lung disease in systemic sclerosis: Diagnostic accuracy in photon-counting-detector and conventional energy-integrating-detector CT
No full textObjectives: To evaluate the performance of automated Lung Texture Analysis (LTA) in assessing interstitial lung disease (ILD) in systemic sclerosis (SSc) using low-dose photon-counting detector CT (PCD-CT) compared to conventional low-dose energy-integrating detector CT (EID-CT). Materials and methods: In this study of a prospectively enrolled SSc cohort, a post-hoc analysis on 186 patients (93 PCD-CT, 93 EID-CT), matched by propensity scoring, was performed. Visual ILD assessment by three expert radiologists served as the reference standard. Image quality assessment was performed using Likert-scales by expert radiologists and signal-to-noise ratios (SNR). Quantitative ILD features and extent were extracted using LTA (Imbio, CALIPER-based). Diagnostic accuracy was assessed using ROC-AUC analysis. Results: LTA-based assessment of ILD on PCD-CT demonstrated a higher AUC for detecting ILD presence (AUC = 0.846) compared to EID-CT (AUC = 0.772). PCD-CT also exhibited superior AUCs in identifying specific ILD features, including ground-glass opacities, reticulation, and honeycombing. However, EID-CT showed higher AUCs than PCD-CT in detecting extensive ILD (>20 % lung involvement; AUC = 0.978 vs. 0.842). Despite significantly lower radiation dose, PCD-CT achieved comparable SNR and superior image quality ratings on Likert-scale. Conclusion: Both EID-CT and PCD-CT demonstrated acceptable to excellent AUC values, indicating their strong applicability in ILD assessment. Further, LTA using PCD-CT consistently provided excellent AUCs for detecting individual ILD features in SSc, supporting its clinical utility despite being trained on PCD-CT data. PCD-CT's enhanced image quality and lower radiation dose make it a promising tool for longitudinal ILD assessment. Further multicenter validation is warranted
La tecnica dell'olio su carta. Storia e conservazione
No full textLa tecnica dell’olio su carta è stata utilizzata dai maggiori artisti del panorama occidentale fin dal XV secolo. Malgrado l’elevato numero di opere superstiti - testimoni principali della storia, dell’evoluzione e delle problematiche conservative - lo studio sistematico della tecnica non trova sufficienti riscontri in letteratura. Tradizionalmente classificata come una rarità all’interno della produzione artistica, l’olio su carta presenta una storia frammentata, contraddistinta da una generale dispersione delle informazioni strettamente connessa all’ibridismo della sua natura materiale, che non consente una collocazione all’interno delle categorie tradizionali del disegno o del dipinto. La peculiarità del dato materiale, che prevede l’utilizzo ed interazione consapevole e ricercata di medium e supporti dalle proprietà chimico fisiche non compatibili, di fatto, ne evidenzia una piena autonomia stilistica. Considerando fonti e opere afferenti e riconducibili principalmente ai secoli XVI e XIX, corrispondenti rispettivamente alla fase di più ampia produzione e a quella di evoluzione della tecnica, il presente studio analizza la tecnica entro tre macro-aree di indagine che offrono i principali elementi per la ricostruzione della sua storia: la ricezione della tecnica nella critica storico-artistica; la disamina delle informazioni presenti nei trattati artistici; le problematiche connesse alla conservazione e restauro. Attraverso un approccio interdisciplinare, che mette in dialogo le discipline storico-artistiche con la diagnostica applicata ai beni culturali, lo studio presenta un documentato contributo per la conoscenza degli aspetti storiografici e tecnici essenziali relativi alla tecnica dell’olio su carta, tra cui i primi risultati delle analisi condotte su specifici casi di studio, insieme alla documentazione dei principali fattori di degrado individuati. La combinazione tra dati storiografici e archivistici, unitamente alle indagini empiriche e diagnostiche delinea un quadro più preciso per la lettura e la comprensione delle opere, fornendo nuove informazioni e strumenti interpretativi, funzionali alla valorizzazione e tutela.Oil painting on paper was employed by leading Western artists from the fifteenth century. Despite the considerable number of surviving works — crucial witnesses to its history, development, and conservation issues — a systematic study of this technique is still largely absent from scholarly literature. Traditionally considered a rarity within artistic production, oil painting on paper has a fragmented history, distinguished by a general scattering of information closely related to its hybrid nature, which prevents a classification within the conventional categories of drawing or painting. The peculiar materiality, characterized by the conscious and deliberate use of media and supports with chemically and physically incompatible properties, in fact reveals a full stylistic autonomy. Focusing primarily on sources and artworks dating from the sixteenth to the nineteenth centuries, corresponding respectively to the periods of greatest production and of technical evolution, this study examines the practice of oil on paper within three main areas of investigation that provide the essential elements for reconstructing its history: the critical reception; the evidence found in artists’ treatises; and the conservation and restoration issues. Through an interdisciplinary approach that connects art-historical research with scientific analysis applied to cultural heritage, the research proposes a documented contribution to the understanding of the key historical and technical aspects of oil painting on paper. It presents the first results of analytical investigations carried out on selected case studies, together with the documentation of the main degradation factors identified. The cross-references between historiographical and archival data, combined with empirical and diagnostic analysis, outline a more precise framework for the interpretation and understanding of the oil painting on paper artworks, providing new insights and interpretative tools useful for their preservation and valorization
The role of cerebellar functional connectivity in upper limb impairment in Multiple Sclerosis
No full textBackground and purpose:
The cerebellum, frequently affected in People with Multiple Sclerosis (PwMS), plays a
fundamental role in motor control, as well as contributes to a range of cognitive functions.
Alterations in cerebellar functional connectivity (FC) are thought to contribute to upper limb
motor impairment, that can be assessed through 9-Hole Peg Test (9HPT). However, the
extent and functional relevance of cerebellar FC alterations underlying upper limb motor
impairment are not yet fully understood. The aim of this study was to assess: 1. Whether FC
abnormalities of the sensori-motor and cognitive cerebellum (smCb and cCb) are associated
with impaired upper limb dexterity; 2. Whether such FC alterations contribute to upper limb
dysfunction, beyond structural brain damage.
Methods:
A total of 667 subjects were selected from the Italian Neuroimaging Network Initiative (INNI)
database. There were 248 PwMS with impaired 9HPT performance (iPwMS), 248 PwMS
with preserved dexterity (pPwMS), and 171 healthy controls (HC).
From multimodal 3 T MRI data we obtained measures of T2-lesion volume (T2-LV), cortical
and deep grey matter volumes (caudate, putamen, and thalamus), cerebellar volumes, and
spinal cord area at the C2–C3 level. Resting-state FC of the smCb and cCb was evaluated
using voxel-wise seed-based analyses. Group comparisons were performed using
ANCOVA models, adjusting for age, sex, and global brain volume in Model 1, for peripheral
GM and global brain volumes, total thalamic and cerebellar volumes, and C2–C3 area as
covariates of no interest in Model 2.
Results:
FC of both smCb and cCb was reduced in PwMS relative to HC. Post hoc analysis using
Model 1 indicated lower FC in iPwMS compared with both pPwMS and HC. After adjusting
for global and regional structural measures in Model 2, significant differences persisted
(albeit at a lower extent) between iPwMS and both groups, whereas FC in pPwMS did not
differ from HC.
Conclusion:
Alterations in cerebellar FC represent a prominent correlate of upper limb disability in pwMS.
The role of cerebellar FC reductions in upper limb impairment is at least primary and not
merely dependent on the brain structural damage. The involvement of both smCb and cCb
suggests that fine motor impairment may reflect widespread cerebellar dysfunction extending beyond purely motor regions, supporting the role of cerebellar connectivity as a
potential biomarker of motor disability and a target for rehabilitative interventions in MS
Accuracy, readability, and understandability of EAU guidelines bot for testicular cancer
No full textPurpose: Recently, the EAU guidelines presented the EAU guidelines bot to assist urologists in the reading of the guidelines; however, up to date, no external validation is available. The aim of our study is to assess the accuracy, completeness, and clarity of the guideline's bot in testicular cancer. Methods: A total of 36 questions based on the EAU testicular cancer guidelines recommendations were developed. Each question was systematically presented to the EAU guidelines bot and the responses were independently assessed by two expert urologists to assess the accuracy, completeness, and clarity. A 5-point Likert scale was used as a score, and in case of discrepancies, a third urologist was queried. Accuracy, completeness, and clarity were assessed per chapter and per grade of recommendation. All questions and answers were recorded in an Excel file. Results: Overall, 36 questions were developed. In terms of accuracy, 36/36 (100%) were defined as excellent (score 5). In terms of completeness, 23/36 (64%) were defined as totally complete (score = 5), 8/36 (22%) presented a good completeness (score = 4), while 5/36 (14%) were fairly complete (score = 3). Finally, in terms of clarity, 31/36 (86%) were defined as totally clear (score = 5) and 5 /36 (14%) were defined as almost totally clear (score = 4). None of the answers was evaluated as non-accurate, non-complete, or non-clear. Conclusions: EAU guidelines bot represents an accurate tool for testicular cancer management
“Come alberi senza radici”: le sfide dell’accoglienza ai giovani migranti nelle narrazioni degli operatori
No full textThe article explores the challenges that operators of reception centers face when working with young migrants. The research analyzes the perspectives of professionals who participated in an experiential training project based on case discussions. Six main themes emerge from the observational reports: learning the Italian language, meeting deadlines, sending money home, the temptation of «easy money», bureaucratic complexities, and difficulties in mutual understanding. The narratives around these themes show the many «voices» involved (regulatory framework, institutions, migrants, families) and the complexity of managing integration requests. Many of such requests are indeed full of paradoxes and difficulties. Operators seem to find themselves amid these tensions alongside their young clients, caught between standard regulatory demands and the reality of individual particular cases. In this complex scenario, the role of the operators is crucial. Not only do they offer services with practical utility, but they also act as a bridge between two worlds that meet and clash, requiring the deployment of intercultural sensitivity and the capacity for empathetic listening
Interoceptive contributions to bodily self-consciousness: insights from theoretical and experimental approaches
No full textThis thesis is organized into four main parts, each addressing a complementary aspect of how interoceptive processes contribute to bodily self-consciousness.
The general aim is to explore, through theoretical synthesis and empirical investigation, the mechanisms by which internal bodily signals support the continuity and stability of self-consciousness. The work combines a systematic review with two empirical studies that progressively move from conceptual clarification to correlational and causal evidence. Chapter 1 provides the theoretical background and rationale for the thesis. It introduces the concept of interoception and dissociation and outlines the growing interest in interoception as a potential key mechanism supporting self-related processing. Chapter 2 presents a systematic review of empirical and theoretical research on the relationship between interoception and dissociation, trying to identify consistent evidence that atypical interoceptive processing is associated with disturbances in self-awareness and self-consciousness. Chapter 3 will examine individual differences in interoception (sensibility and accuracy) in relation to susceptibility to transient alterations in bodily self-consciousness and self perception during the Mirror Gazing Task. Chapter 4 will introduce an experimental manipulation of interoceptive–exteroceptive coherence. Using real-time auditory heartbeat feedback during the Mirror Gazing Task, it will investigate how temporal synchrony or asynchrony between internal and external bodily cues modulates self-perception and dissociative-like experiences. The final section (Chapter 5) will integrate findings across the three studies. It discusses the implications of the results within predictive and interoceptive coding accounts of self-consciousness, emphasizing how coherence between internal and external bodily signals underlies the stability of bodily self-consciousness. Methodological considerations and future research directions are outlined, along with the potential relevance of this work for understanding the mechanisms underlying the relationship between interoception, dissociation and other self-related
disturbances
Impact of 10% thymoquinone-standardized Nigella sativa oily extract on 24-hour blood pressure profile and nocturnal dipping: a subgroup analysis of a pilot study in postmenopausal hypertensive women
No full textNo abstract availabl
Secrecy Preservation for Online Process Monitoring with Trusted Execution Environment
No full textThe online monitoring of collaborative business processes involves the integration of event data sourced from various information systems into a unified process state. The transmission of process records across organizational boundaries poses significant data secrecy and security challenges. In this context, organizations may be reluctant to outsource sensitive data with their collaborators to update a global process state. In this paper, we propose ProMTEE, a novel framework designed to tackle these challenges by resorting to trusted applications running in Trusted Execution Environments (TEEs). To showcase the potential of ProMTEE, we contextualize its four-staged interaction protocol within the realm of two online monitoring tasks, namely, control flow tracking and compliance monitoring. We verify the security of our solution through a threat analysis against a set of security requirements derived from a supply-chain scenario. In addition, we conduct an experimental assessment of our proof-of-concept implementation with tests on memory usage and latency using real-world datasets
Tritium transport analysis and modeling for magnetically confined fusion reactors considering different scales
No full textTritium management represents a fundamental challenge for commercial fusion energy development. The power plant should be self-sufficient with respect to its fuel and ensure sufficient startup inventory for subsequent reactors. The fuel cycle must ensure technical feasibility of self-sufficiency while addressing regulatory considerations related to inventory and release limits. The challenges associated with tritium management span multiple physical scales and time-frames, requiring advanced numerical tools capable of accurately predicting tritium behaviour across a wide range of contexts. These tools are essential for providing engineering insights that support reactor design optimization. The understanding of main fuel cycle dynamics and the development of reliable computational models for tritium transport analysis are crucial enabling steps for the successful implementation of fusion energy systems.
This thesis presents a comprehensive investigation of tritium pathways in fusion power plants through systematic analysis of component, system, and reactor-level phenomena. Collaborations with Eni S.p.A., ENEA, and the Karlsruhe Institute of Technology (KIT) were fundamental in tackling the different topics and carrying out the work here presented. The research addresses critical methodological gaps in understanding tritium behaviour across interfaces and interconnected systems that define fusion reactor operations, with particular emphasis on fuel cycle dynamics. A hierarchical methodology, progressing from component-scale to reactor-scale phenomena, is employed, and analyses focus on multiple reactor designs to provide more general insights. Three computational tools were developed to address unique requirements at each considered scale. At component scale, the \textvtt{pastaFoam} solver, built with the OpenFOAM framework, provides computational fluid dynamics capabilities for transient tritium transport in coupled fluid-solid domains. At system-level, SAETTA, a modular transport code implemented in Python, allows for flexible analysis of networks of components and 1D domains. Finally, at reactor-level, MINERVA, a fuel cycle simulation framework developed using Julia's ModelingToolkit, enables rapid fuel cycle architecture assessment and parametric studies. Where possible, computational tools underwent rigorous verification and validation through comparison with analytical solution and experimental data, and through code-to-code benchmarks.
Component-scale analysis focused on heat exchanger performance using an ARC-class reactor Double Wall Heat Exchanger (DWHX) design as case study, investigating fundamental trade-offs between thermal performance, tritium barrier efficiency, and extraction capabilities. System-level investigation extends the scope from heat exchanger to an entire cooling system, analysing the EU DEMO Water-Cooled Lead-Lithium (WCLL) Breeding Blanket (BB) Primary Heat Transfer System (PHTS). Tritium migration pathways, coolant chemistry evolution, and losses to building rooms are studied under transient conditions. Reactor-level analysis extended the scope even further, considering the whole fuel cycle architecture. A four-loop architecture is proposed and studied. Theoretical impurity limits in the reactor chamber are assessed and the effect of fuel bypass recycling in conjunction with Direct Internal Recycling (DIR) is investigated both on the Inner Fuel Cycle (IFC) alone and on the entire fuel cycle, with a full implementation of the proposed architecture in MINERVA.
The results of the verification and validation efforts of \textvtt{pastaFoam} are considered satisfactory and the tool has proven to be suitable for component-level simulations. Component-scale analysis of the DWHX demonstrated effective tritium barrier performance, with limited permeation to secondary coolant. However, the efficiency of tritium extraction via the helium gap for fuel recycling purposes was found to be limited. These findings identify local source and sink terms that govern system-level inventory dynamics and inform larger-scale design considerations. \newline
In the system-level investigation of the EU DEMO BB PHTS, the tritium inventory in the primary coolant and connected rooms has been estimated, along with loss rates. Key factors impacting inventories and losses under reference conditions include the size of the Coolant Purification System (CPS) and potential leaks from piping. Additionally, the study discusses the acceptable limits for tritium concentration in the air. The effects of leaks, CPS size, hydrogen concentration in the water, and Permeation Reduction Factors (PRF) at the steam generator walls have also been evaluated. Also for SAETTA, a comprehensive verification and validation campaign has been specifically designed and performed to demonstrate the code capabilities in a wide range of fusion-related applications.\newline
Concerning the fuel cycle, protium build-up is identified as a potential challenge, with accumulation becoming problematic at high separation efficiencies without dedicated removal systems. Results demonstrate that the proposed architecture effectively manages impurity concentrations below 1% for protium while maintaining optimal D-T ratios through active control systems. The proposed architecture achieves significant reductions in external fuel requirements, with effective conversion ratios growing exponentially with DIR separation efficiency. The bypass loop successfully provides the majority of gas puffing requirements without causing excessive impurity accumulation. A working, self-sufficient steady state configuration of the fuel cycle is obtained, to which a maximum bypass fraction is associated. Sensitivity studies reveal a critical DIR fraction threshold below which external tritium source become necessary and confirm that the use of fuel recycling, both bypass and DIR, globally leads to a more efficient fuel cycle with reduced inventories.
This work establishes a comprehensive numerical and methodological framework for multi-scale tritium management in fusion power plants, demonstrating how design decisions at component level propagate through system architectures to determine fuel cycle requirements and operational constraints. The development of three specialised computational tools provides the fusion community with capabilities spanning from detailed transport phenomena analysis to complete fuel cycle architecture assessment. Future work will focus on integrating these capabilities together, using MINERVA as a platform to incorporate SAETTA features and interface with component-level codes such as pastaFoam. The fuel cycle study presented lays the groundwork for more integrated fuel cycle optimization activities. Unit operations based on domain physics equations for common technologies will be implemented, along with improved lumped models of critical interfaces such as the reactor chamber, breeding blanket and room ventilation.\newlin