Archivio della ricerca - Fondazione Bruno Kessler
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Search for ttH/A→tttt production in proton–proton collisions at √s = 13 TeV with the ATLAS detector
No full textSearch for the jet-induced diffusion wake in the quark-gluon plasma via measurements of jet-track correlations in photon-jet events in Pb+Pb collisions at √sNN=5.02TeV with the ATLAS detector
No full textThis paper presents a measurement of jet-track correlations in photon-jet events, using 1.72 nb−1 of Pb+Pb data at √sNN=5.02TeV recorded with the ATLAS detector at the LHC. Events with energetic photon-jet pairs are selected, where the photon and jet are approximately back-to-back in azimuth. The angular correlation between jets and charged-particle tracks with transverse momentum (pT) in the range 0.5–2.0 GeV in the hemisphere opposite to the jet, |Δφ(jet,track)|>π/2, is measured as a function of their relative pseudorapidity difference, |Δη(jet,track)|. In central Pb+Pb collisions, these correlations are predicted to be sensitive to the diffusion wake in the quark-gluon plasma resulting from the lost energy of high-pT partons traversing the plasma, with a characteristic modification as a function of |Δη(jet,track)|. The correlations are examined with different selections on the jet-to-photon pT ratio to select events with different degrees of energy loss. No diffusion wake signal is observed within the current sensitivity and upper limits at 95% confidence level on the diffusion wake amplitude are reported
Comparing the effectiveness of ring and block-vaccination strategies on networks
No full text: Vaccination is vital for preventing disease spread, as demonstrated by its role played in recent outbreaks such as measles, COVID-19, and the 2014 West Africa Ebola crisis. Classical ring vaccination-targeting individuals near infected cases to form protective clusters-has become of interest due to its effectiveness, yet it is strongly influenced by the quality of contact tracing and availability of medical resources. Here, we model the efficiency of a family of ring vaccination-inspired strategies that address these limiting factors and disentangle them from the structure of the contact patterns. In particular, we evaluate scenarios that consider a vaccination radius r, used to vaccinate nodes in the network up to r contacts away (block vaccination) or exactly r contacts away (ring vaccination) from nodes of interest. Each one of these is tested under two further scenarios: the preventive one, where individuals are vaccinated before the epidemic takes place, and the containment one, where vaccination occurs during an outbreak to limit disease spread. They are tested in synthetic networks, where we find that in the preventive scenario, ring outperforms block vaccination, reducing the size of the epidemic and, in some cases, even preventing it from happening. On the other hand, in the containment scenario, we find that both strategies perform slightly similarly in reducing the impact of the diseases but block vaccination using fewer resources. As a case study, the proposed strategies are used to create epidemiological risk maps by employing the spatial position of olive trees in the Salento region in Italy, which recently suffered the impact of the bacterium Xylella fastidiosa
A methodology for the experimental performance evaluation of Access Control enforcement mechanisms based on business processes
No full textWhile the security analysis of Access Control (AC) policies has received a lot of attention, the same cannot be said for their enforcement. As applications become more distributed, centralized services a bottleneck, and legal compliance constraints stricter (e.g., the problem of honest but curious Cloud providers in the light of privacy regulations), the fine-tuning of AC enforcement mechanisms is likely to become more and more important. This is especially true in scenarios where the quality of service may suffer from computationally heavy security mechanisms and low latency is a prominent requirement. As a first step towards a principled approach to fine-tune AC enforcement mechanisms, this paper introduces a methodology providing the means to measure the performance of such mechanisms through the simulation of realistic scenarios. To do so, we base our methodology on Business Process Model and Notation (BPMN) workflows — that provide for an appropriate abstraction of the sequences of requests (e.g., access a resource, revoke a permission) sent toward AC enforcement mechanisms — to evaluate and compare the performance of different mechanisms. We implement our methodology and use it to evaluate three AC enforcement mechanisms representative of both traditional centralized — i.e., the Open Policy Agent (OPA) and the eXtensible Access Control Markup Language (XACML) — and decentralized AC — i.e., the CryptoAC tool
A Smart Planar Antenna Based on a Reconfigurable Parasitic Structure Activated by RF-MEMS Switches
No full textThis work proposes a smart planar microstrip antenna that can be reconfigured and controlled by RF-MEMS, and is based on a reconfigurable parasitic structure. The antenna structure is based on an omnidirectional active element surrounded by a series of reconfigurable parasitic microstrip elements, which are connected to RF-MEMS switches that are used to electronically modify the state of the parasitic elements. The goal of the parasitic microstrip structure is to permit the steering of the main lobe of the antenna, place zeros in the radiation pattern in order to avoid interfering signals and maximize the signal-to-noise ratio. The prototype of the antenna was designed, fabricated and assessed experimentally. To assess the effectiveness and potentialities of the proposed prototype, some representative numerical and experimental results are reported and compared
La rivoluzione quantistica. Fisica, antropologia, religione
No full textLa rivoluzione quantistica, sebbene abbia già trasformato profondamente la nostra quotidianità grazie a tecnologie come il GPS, i laser e i computer, resta ancora ai margini della riflessione umanistica. Eppure, le sue implicazioni filosofiche, culturali e simboliche sono tali da interrogare l'intero modo in cui concepiamo la realtà. Quali possibilità si aprono se l'antropologia, la filosofia e gli studi religiosi si confrontano con la fisica delle particelle? Che cosa può nascere da un dialogo tra saperi apparentemente lontani? È attorno a questi interrogativi che si sviluppano i contributi di questo numero della rivista, che esplorano - con linguaggi e metodi differenti - le connessioni tra scienze dure e scienze umane, in una prospettiva transdisciplinare, capace di restituire la complessità del reale
Benchmarking Machine Learning for Sentiment Analysis: A Case Study of News Articles in Multiple Languages
No full textSentiment analysis is the field of study that analyzes people’s opinions and sentiments towards entities such as products, services and organizations. Brand reputation analysis, competitive intelligence and social network analysis are just a few areas that can benefit from sentiment analysis. Most studies on sentiment analysis have only focused on domains like product reviews and social network content, leaving sentiment inference in the news domain under-investigated. In this work, we use a case study of a company specialized in the analysis of brand reputation to evaluate machine learning models for sentiment analysis on multilingual news articles. Several models were tested, including traditional machine learning models like KNN, and transformer-based models like BERT, Llama and GPT. The implemented models were evaluated on a dataset of Italian, German and Ladin news articles annotated with their sentiment polarity. Overall, our experiments show state-of-the-art results and confirm the outcomes of previous studies, i.e. that sentiment analysis of news articles remains a complex task. Machine learning systems can support manual annotators in accelerating the annotation process. Our findings can provide a benchmark for researchers in natural language processing when performing sentiment analysis of news articles
Development of a miniaturized electrochemical biochip
Get PDFThe technological evolution towards portable systems for nucleic acids (NAs) analysis is central in diagnostics and healthcare. Conventional approaches for genetic analysis require multistep procedures, from the genetic material purification to its detection, that are mostly based on the NA amplification by polymerase chain reaction (PCR) and constrained to bulky specialized instruments and dedicated laboratories. These limitations imply an increase in time and cost of analysis avoiding the possibility of massive molecular screening, as in the case of an infectious pandemic, and accessible diagnosis. Therefore, research efforts are moving towards new Lab-on-a-chip (LoC) technologies that guarantee a more integrated, decentralized, user-friendly, and low-cost NA analysis. These are based on miniaturized optical or electrical chips on which it is possible to integrate a sensing surface for specific analytical applications. In this scenario, we presented the fabrication and characterization of a miniaturized electrochemical (EC) biochip as a potential LoC for genetic applications. The chip was developed with microfabricated electrodes on top and polycarbonate/PDMS microchambers for the surface treatment and functionalization. The characterization of chip EC performances has been performed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Moreover, the chip surface has been functionalized with thiol-modified oligonucleotides, whose immobilization has been characterized by contact angle (CA) and surface free energy (SFE) analysis. Results reported a good robustness and responsivity of the chip proving its suitability for sensing array preparation and integration in a LoC format
Shallow Nitrogen Vacancy Color Centers in Diamond by Ion Implantation
No full textRecent advancements in quantum technologies are fueled by the ability to engineer materials with specific quantum properties, enabling various applications. The nitrogen-vacancy (NV) center in diamond is a key system for nanoscale sensors, capable of detecting weak magnetic fields with nanotesla-range sensitivity. To achieve high spatial resolution and sensitivity, NV centers must be placed near the diamond surface. This study investigates the creation of NV defects in a pure chemical vapor deposition (CVD) diamond single crystal via broad-beam ion implantation. The implantations are performed through thin (100 nm) SiO2 layers deposited by plasma-enhanced CVD (PECVD). Both normal and oblique ion beam incidences are used, with the oblique incidence chosen to reduce the nitrogen ion penetration depth. Simulations show a subsurface NV center distribution, with the highest concentration near the surface; the expected trends are confirmed by angle-resolved X-ray photoelectron spectroscopy (ARXPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). This distribution extends to a depth of 30 nm. By adjusting the ion beam incidence angle, NV center density can be modulated. This work contributes to optimizing the fabrication process for shallow color centers through ion implantation using a screening layer
Degenerazioni e rigenerazioni della democrazia: una lezione
No full textSi tratta della traduzione della trascrizione, autorizzata dall'autore, della conferenza "Degenerations of Democracy", tenuta da Charles Taylor a Trento il 12 gennaio 2023. Taylor, uno dei filosofi politici più influenti dell'ultimo secolo, propone nel testo una lettura panoramica dell’evoluzione recente di alcune delle più importanti democrazie occidentali al fine di ricavare qualche lezione generale e, per quanto possibile, motivi di speranza nella vitalità della promessa democratica