Quantifying Credit Portfolio sensitivity to asset correlations with interpretable generative neural networks

In this research, we propose a novel approach for the quantification of credit portfolio Value-at-Risk (VaR) sensitivity to asset correlations with the use of synthetic financial correlation matrices generated with deep learning models. In previous work Generative Adversarial Networks (GANs) were employed to demonstrate the generation of plausible correlation matrices, that capture the essential characteristics observed in empirical correlation matrices estimated on asset returns. Instead of GANs, we employ Variational Autoencoders (VAE) to achieve a more interpretable latent space representation. Through our analysis, we reveal that the VAE latent space can be a useful tool to capture the crucial factors impacting portfolio diversification, particularly in relation to credit portfolio sensitivity to asset correlations changes

Fatigue assessment of Ti-6Al-4V titanium alloy laser welded joints in absence of filler material by means of full-field techniques

The aim of this research activity was to study the fatigue behavior of laser welded joints of titanium alloy, in which the welding was performed using a laser source and in the absence of filler material, by means of unconventional full field techniques: Digital Image Correlation (DIC), and Infrared Thermography (IRT). The DIC technique allowed evaluating the strain gradients around the welded zone. The IRT technique allowed analyzing the thermal evolution of the welded surface during all the fatigue tests. The fatigue limit estimated using the Thermographic Method corresponds with good approximation to the value obtained from the experimental fatigue tests. The obtained results provided useful information for the development of methods and models to predict the fatigue behavior of welded T-joints in titanium alloy

Diagnostic investigation of the Cycle of the new church of Sarria (Floriana, Malta) by Mattia Preti

In the present paper, we present the main results of a diagnostic investigation on different paintings by Mattia Preti, belonging to the Cycle of the New Church of Sarria, located inside the Church of the Immaculate Conception of Sarria (Floriana) in Malta. The analysis was carried out on the occasion of the restoration process and, due to the short time available, only on some representative areas of each painting. A multi-technique approach was applied in situ, employing X-ray fluorescence spectroscopy (XRF) and Raman microscopy. The aim was to achieve information on the execution technique, in a completely non-invasive way, following the requirements of the restorers.peer-reviewe

P1245 Polymorphic Variants of HSD3B1 Gene Confer Different Outcome in Specific Subgroups of Patients Infected With SARS-CoV-2

Introduction: Severe respiratory syndrome coronavirus 2 (SARS-CoV-2) uses the androgen receptor (AR), through ACE2 receptor and TMPRSS2, to enter nasal and upper airways epithelial cells. Genetic analyses revealed that HSD3B1 P1245C polymorphic variant increases dihydrotestosterone production and upregulation of TMPRSS2 with respect to P1245A variant, thus possibly influencing SARS-CoV-2 infection. Our aim was to characterize the HSD3B1 polymorphism status and its potential association with clinical outcomes in hospitalized patients with COVID-19 in Southern Switzerland. Materials and Methods: The cohort included 400 patients hospitalized for COVID-19 during the first wave between February and May 2020 in two different hospitals of Canton Ticino. Genomic DNA was extracted from formalin-fixed paraffin-embedded tissue blocks, and HSD3B1 gene polymorphism was evaluated by Sanger sequencing. Statistical associations were verified using different test. Results: HSD3B1 polymorphic variants were not associated with a single classical factor related to worse clinical prognosis in hospitalized patients with SARS-CoV-2. However, in specific subgroups, HSD3B1 variants played a clinical role: intensive care unit admission was more probable in patients with P1245C diabetes compared with P1245A individuals without this comorbidity and death was more associated with hypertensive P1245A>C cases than patients with P1245A diabetes without hypertension. Discussion: This is the first study showing that HSD3B1 gene status may influence the severity of SARS-CoV-2 infection. If confirmed, our results could lead to the introduction of HSD3B1 gene status analysis in patients infected with SARS-CoV-2 to predict clinical outcome. Keywords: HSD3B1 gene polymorphism; Likelihood-ratio tests; SARS-CoV-2; androgen receptor; direct sequencing

Digital reconstruction and scientific analysis prior the restoration of two paintings by Mattia Preti in the Church of the Immaculate Conception of Sarria (Floriana, Malta)

The paper presents the results of scientific investigations carried out in support of a professionally executed restoration on two paintings by Mattia Preti, located in the Church of the Immaculate Conception of Sarria in Floriana, Malta. In particular, the attention was mainly paid on a combined approach, using 2D/3D survey in order to formulate hypothetic reconstruction, and XRF spectroscopy in order to get more information on how the master prepared the various types of materials, with particular regard to the painting preparation, the pigments palette and the formulation of shades and highlights.peer-reviewe

Scientific investigation of The Conversion of St Paul painting (Mdina, Malta)

The paper presents the results of two different approaches applied to the newly-restored painting The Conversion of St Paul, the main altarpiece in the Cathedral of Mdina in Malta. This large, dramatic painting is work of the Baroque artist Mattia Preti, il Cavaliere Calabrese. As is normal with a professionally executed restoration, several scientific methods have been used before, during and at completion, in the framework of a global analytical strategy. In particular, we focus on the results of the digital photogrammetric survey which uses image-based approaches for 2D/3D models reconstruction enormously. The model was used to quantify and measure important features on the painting as well extensions of areas restored. In addition, portable Raman spectroscopy was used to identify, in non-destructive way, the nature of the painting materials with the final goal of reconstructing the color palette of the artist.peer-reviewe

Valorizing underground cultural heritage through the use of virtual reality

This paper presents the results of scientific investigations carried out at the Batia Church which is located in the small village of Tortorici (Messina, Sicily, Italy). We performed several geophysical surveys, as well as geomatics approaches, were used in order to reconstruct 2D and 3D digital models of the monument mainly using digital photogrammetry. Previous geophysical investigations have shown the presence of a crypt which was ultimately surveyed and digitally reconstructed. Here, we present the potential of valorizing the site and its underground structures by the means of advanced technologies and digital reconstructions.peer-reviewe

Microwave Linear Characterization Procedures of On-Wafer Scaled GaAs pHEMTs for Low-Noise Applications

This contribution deals with the microwave linear characterization and noise figure measurement of four on-wafer GaAs pseudomorphic high-electron mobility transistors having scaled gate widths. The proposed measurement campaign has been fulfilled in two different laboratories: The University of Messina, Italy and US Naval Research Laboratory, Washington, DC, USA. Two equivalent approaches have been straightforwardly employed: a standard tuner-based technique and a novel tuner-less technique. The effectiveness of the novel technique has been confirmed as carried out independently by the two laboratories, evidencing the benefits of both techniques. The proposed experimental activity highlights the applicability of the tunerless technique for the noise characterization of advanced on-wafer devices without the constraint imposed by the addition of a source tuner to the standard measurement setup

A combined 3D surveying, XRF and Raman in-situ investigation of The Conversion of St Paul painting (Mdina, Malta) by Mattia Preti

This paper presents the results of three different approaches applied to the newly-restored titular painting entitled The Conversion of St Paul, the main altarpiece in the Mdina Cathedral in Malta. This large, dramatic painting is the work of the Baroque artist, Mattia Preti, known as il Cavaliere Calabrese. Here, we focus on the results of the digital photogrammetric survey that adopts image-based approaches for 2D/3D model reconstruction. The model was used to quantify important features of the painting as well extensions of the areas restored. In addition, portable X-ray fluorescence and Raman spectroscopies were used to non-destructively identify the nature of the painting materials, at the elemental and molecular spatial scales, respectively, with the ultimate goal of reconstructing the colour palette of the artist. The 3D model developed here could be applied to other paintings of Preti to conduct comparisons between different measurements in the paintings, with the main goal of clarifying the technique used by the artist. This information, along with the characterisation of the materials used, is crucial for the reconstruction of the historical–geographical context of the artwork, since specific pigmenting agents and media tend to represent the stylistic expression of an artist or an epoque.peer-reviewe