Entanglement asymmetry in the ordered phase of many-body systems: the Ising Field Theory

Global symmetries of quantum many-body systems can be spontaneously broken. Whenever this mechanism happens, the ground state is degenerate and one encounters an ordered phase. In this study, our objective is to investigate this phenomenon by examining the entanglement asymmetry of a specific region. This quantity, which has recently been introduced in the context of $U(1)$ symmetry breaking, is extended to encompass arbitrary finite groups $G$. We also establish a field theoretic framework in the replica theory using twist operators. We explicitly demonstrate our construction in the ordered phase of the Ising field theory in 1+1 dimensions, where a $\mathbb{Z}_2$ symmetry is spontaneously broken, and we employ a form factor bootstrap approach to characterise a family of composite twist fields. Analytical predictions are provided for the entanglement asymmetry of an interval in the Ising model as the length of the interval becomes large. We also propose a general conjecture relating the entanglement asymmetry and the number of degenerate vacua, expected to be valid for a large class of states, and we prove it explicitly in some cases

Analisi di prove di tenacita a frattura interlaminare mediante VCCT: effetti tridimensionali e validazione

L’ambito di studio di questa tesi è quello del danno interlaminare nei materiali compositi stratificati e la loro analisi mediante metodi ad elementi finiti. Lo scopo principale delle attività che sono state oggetto di questa tesi è quello d’individuare le problematiche che si possono presentare nella simulazione numerica delle prove per i modi di apertura I e II della fessura. A tale proposito è necessario simulare la prova con modelli ad elementi finiti; una volta che è stata riprodotta è possibile apprezzare alcuni fenomeni locali che non sono direttamente osservabili durante la prova. I valori di tenacità a frattura interlaminare ottenuti dalle prove sperimentali sono misure di tipo indiretto e sono ricavati attraverso modelli analitici che trascurano eventuali effetti tridimensionali, mentre i modelli FEM che sono stati usati in questa attività sono invece di tipo tridimensionale. Per simulare queste prove occorre individuare le differenze con i modelli bidimensionali e di conseguenza interpretare il significato dei risultati sperimentali. Questa tipologia di test prevede la propagazione di delaminazioni sotto l’effetto dei carichi applicati. È possibile riprodurre questo fenomeno sfruttando una tecnica numerica che permette di simulare la propagazione di difetti anche in modelli tridimensionali con modi di apertura misti della fessura: la Virtual Crack Closure Technique. La VCCT è implementata anche nei codici di tipo commerciale, durante questa attività si è fatto uso di Abaqus. Un altro obiettivo è capire come impostare i parametri di controllo e infine quello della validazione della VCCT con risultati ottenuti sperimentalmente in modo da rendere possibile il suo futuro utilizzo su analisi di componenti strutturali per la verifica a damage tolerance

The hypoxic transcription factor KlMga2 mediates the response to oxidative stress and influences longevity in the yeast Kluyveromyces lactis

Hypoxia is defined as the decline of oxygen availability, depending on environmental supply and cellular consumption rate. The decrease in O2 results in reduction of available energy in facultative aerobes. The response and/or adaptation to hypoxia and other changing environmental conditions can influence the properties and functions of membranes by modifying lipid composition. In the yeast Kluyveromyces lactis, the KlMga2 gene is a hypoxic regulatory factor for lipid biosynthesis-fatty acids and sterols-and is also involved in glucose signaling, glucose catabolism and is generally important for cellular fitness. In this work we show that, in addition to the above defects, the absence of the KlMGA2 gene caused increased resistance to oxidative stress and extended lifespan of the yeast, associated with increased expression levels of catalase and SOD genes. We propose that KlMga2 might also act as a mediator of the oxidative stress response/adaptation, thus revealing connections among hypoxia, glucose signaling, fatty acid biosynthesis and ROS metabolism in K. lactis

Risk management nelle attività con l'estero - Il caso Fosber S.p.A. -

Questa tesi affronta l'esposizione ai rischi derivanti dalle attività con l'estero (rischio di credito con aziende estere e rischio di cambio) e la relativa attività di risk management. In particolare, viene analizzata l'esposizione e la gestione del rischio di una media impresa toscana: la Fosber S.p.A.. Tale azienda, inserita nel tessuto economico italiano ed europeo, ha una spiccata vocazione internazionale ed è stata, quindi, adatta per l'analisi dell'esposizione aziendale ai rischi derivanti dall'estero e ad una valutazione delle possibili strategie di copertura

Survival analysis using the Covid-death mean-imputation (CoDMI) algorithm: a first clinical application in radiation oncology

Background/Aim: To report long-term survival results after trimodal approach for locally advanced rectal cancer (LARC) in the Covid-19 era. We herein illustrate a clinical application of Covid-death mean-imputation (CoDMI) algorithm in LARC patients with Covid-19 infection. Patients and Methods: We analyzed 94 patients treated for primary LARC. Overall survival was calculated in months from diagnosis to first event (last follow-up/death). Because Covid-19 death events potentially bias survival estimation, to eliminate skewed data due to Covid-19 death events, the observed lifetime of Covid-19 cases was replaced by its corresponding expected lifetime in absence of the Covid-19 event using the CoDMI algorithm. Patients who died of Covid-19 (DoC) are mean-imputed by the Kaplan-Meier estimator. Under this approach, the observed lifetime of each DoC patient is considered as an "incomplete data" and is extended by an additional expected lifetime computed using the classical Kaplan-Meier model. Results: Sixteen patients were dead of disease (DoD), 1 patient was DoC and 77 cases were censored (Cen). The DoC patient died of Covid-19 52 months after diagnosis. The CoDMI algorithm computed the expected future lifetime provided by the Kaplan-Meier estimator applied to the no-DoC observations as well as to the DoC data itself. Given the DoC event at 52 months, the CoDMI algorithm estimated that this patient would have died after 79.5 months of follow-up. Conclusion: The CoDMI algorithm leads to "unbiased" probability of overall survival in LARC patients with Covid-19 infection, compared to that provided by a naive application of Kaplan-Meier approach. This allows for a proper interpretation/use of Covid-19 events in survival analysis. A user-friendly version of CoDMI is freely available at https://github.com/alef-innovation/codmi

Reduced representation libraries from DNA pools analysed with next generation semiconductor based-sequencing to identify SNPs in extreme and divergent pigs for back fat thickness

The aim of this study was to identify single nucleotide polymorphisms (SNPs) that could be associated with back fat thickness (BFT) in pigs. To achieve this goal, we evaluated the potential and limits of an experimental design that combined several methodologies. DNA samples from two groups of Italian Large White pigs with divergent estimating breeding value (EBV) for BFT were separately pooled and sequenced, after preparation of reduced representation libraries (RRLs), on the Ion Torrent technology. Taking advantage from SNAPE for SNPs calling in sequenced DNA pools, 39,165 SNPs were identified; 1/4 of them were novel variants not reported in dbSNP. Combining sequencing data with Illumina PorcineSNP60 BeadChip genotyping results on the same animals, 661 genomic positions overlapped with a good approximation of minor allele frequency estimation. A total of 54 SNPs showing enriched alleles in one or in the other RRLs might be potential markers associated with BFT. Some of these SNPs were close to genes involved in obesity related phenotypes

An Improved Strategy for Detection and Localization of Nodules in Liver Tissues by a 16 MHz Needle Ultrasonic Probe Mounted on a Robotic Platform

This study presents an improved strategy for the detection and localization of small size nodules (down to few mm) of agar in excised pork liver tissues via pulse-echo ultrasound measurements performed with a 16 MHz needle probe. This work contributes to the development of a new generation of medical instruments to support robotic surgery decision processes that need information about cancerous tissues in a short time (minutes). The developed ultrasonic probe is part of a scanning platform designed for the automation of surgery-associated histological analyses. It was coupled with a force sensor to control the indentation of tissue samples placed on a steel plate. For the detection of nodules, we took advantage of the property of nodules of altering not only the acoustical properties of tissues producing ultrasound attenuation, but also of developing patterns at their boundary that can modify the shape and the amplitude of the received echo signals from the steel plate supporting the tissues. Besides the Correlation Index Amplitude (CIA), which is linked to the overall amplitude changes of the ultrasonic signals, we introduced the Correlation Index Shape (CIS) linked to their shape changes. Furthermore, we applied AND-OR logical operators to these correlation indices. The results were found particularly helpful in the localization of the irregular masses of agar we inserted into some excised liver tissues, and in the individuation of the regions of major interest over which perform the vertical dissections of tissues in an automated analysis finalized to histopathology. We correctly identified up to 89% of inclusions, with an improvement of about 14% with respect to the result obtained (78%) from the analysis performed with the CIA parameter only