EVALUATING THE ACCURACY OF TAIL RISK FORECASTS FOR SYSTEMIC RISK MEASUREMENT

In this paper we address how to evaluate tail risk forecasts for systemic risk measurement. We propose two loss functions, the Tail Tick Loss and the Tail Mean Square Error, to evaluate, respectively, CoVaR and MES forecasts. We then analyse CoVaR and MES forecasts for a panel of top US financial institutions between 2000 and 2012 constructed using a set of bivariate DCC-GARCH-type models. The empirical results highlight the importance of using an appropriate loss function for the evaluation of such forecasts. Among other findings, the analysis confirms that the DCC-GJR specification provides accurate predictions for both CoVaR and MES, in particular for the riskiest group of institutions in the panel (Broker-Dealers)

Modelli neuro-computazionali di memoria semantica: analisi dell'apprendimento dipendente dal contesto e sincronismo neurale

I meccanismi neurali di memoria semantica sono fondamentali per capire deficit di conoscenza. Sono stati sviluppati modelli per lo studio della memoria per capire come la conoscenza del significato concettuale sia immagazzinata nel sistema nervoso. Un tipo di rete neurale è quella basata su dinamiche attrattive: informazioni che caratterizzano i concetti vengono espresse dall'attivazione simultanea di gruppi neuronali codificanti proprietà. La semantica di un concetto si descrive tramite collezioni di features che sintetizzano la conoscenza del concetto. Attraverso l'apprendimento sinaptico, un concetto viene memorizzato come punto di equilibrio; l'informazione completa si ripristina a partire da un punto iniziale. Le reti attrattive basate su proprietà forniscono intuizioni su fenomeni riguardanti la memoria in condizioni normali e patologiche. Questi modelli spiegano il ruolo delle features nella rappresentazione e la distinzione tra concetti subordinati e sovraordinati, presupponendo un ruolo diverso nell'archiviazione e nel ripristino. Nel presente lavoro, è stato esteso un modello di rete semantica monodimensionale e si sono indagati i meccanismi che portano alla formazione di categorie. Si vuole comprendere come le connessioni tra proprietà siano indotte dall’esperienza. La semantica di un oggetto dipende dal contesto, ovvero da proprietà che tendono a verificarsi insieme. Si studia infine un modello con oscillatori per mantenere in memoria differenti rappresentazioni. La sincronizzazione consente il ripristino simultaneo di concetti diversi risolvendo il problema di “binding & segmentation”. Le simulazioni mostrano come, evocando alcune features, siano richiamate le proprietà salienti; i risultati forniscono indicazioni sui meccanismi neurali usati per formare le categorie. La rete risolve compiti di riconoscimento concettuale, mantenendo la distinzione tra categorie e singoli membri, e discriminando tra features salienti e marginali

Essays in the Econometric Analysis of Systemic Risk Measures

This thesis aims at the study of systemic risk measurement, which became crucial after the 2007 − 2009 financial crisis. The objective of the thesis is twofold: (i) we address the issue of assessing the accuracy of systemic risk measures, (ii) we investigate the role of the long-range dependence in systemic risk forecasting, under both methodological and empirical perspectives. From the methodological point of view, we propose two appropriate loss functions, the Tail Tick Loss function and the Tail Mean Square Error, specifically designed to evaluate the CoVaR and MES accuracy, respectively. Moreover, we introduce a comprehensive model called Asymmetric-Component-GARCH (ACGARCH), which is able to capture both the leverage effect and long-range dependence. An empirical analysis of different bivariate volatility models to the daily returns of 91 US financial institutions in the period 2000 − 2012 confirms the need of employing appropriate loss functions to evaluate systemic risk accuracy and to discriminate among different competing models. Moreover, empirical results encourage the usage of the ACGARCH model in the systemic risk framework

A case of cystic fibrosis

As the expected survival improves for patients with cystic fibrosis (CF), there is a growing population of adults with this disease. We describe a case of a 33-year-old woman with CF presenting with recurrent pancreatitis, malnutrition, borderline sweat test and respiratory diseases. The case report underlines the importance of diagnosis and management of CF in adults, and the important role played by the Family Physician in developing an adult care program

Effectiveness of a video lesson for the correct use in an emergency of the automated external defibrillator (AED)

Background and aim of the work: Every year around 275 thousand people in Europe and 420 thousand in the United States are affected by sudden cardiac arrest. Early electrical defibrillation before the arrival of emergency services can improve survival. Training the population to use the AED is essential. The training method currently in use is the BLSD course, which limits training to a population cohort and may not be enough to meet the requirements of the proposed Law no. 1839/2019. This study aims to verify the effectiveness of an online course that illustrates the practical use of the AED to a population of laypeople. Methods: An observational study was conducted to compare a lay population undergoing the view of a video spot and a cohort of people who had participated in BLSD Category A courses. The performances of the two groups were measured immediately after the course and 6 months later. Results: Overall, the video lesson reported positive results. Six months later the skills were partially retained. The cohort that followed the video lesson showed significant deterioration in the ability to correctly position the pads and in safety. Conclusions: Although improved through significant reinforcements, the video spot represents a valid alternative training method for spreading defibrillation with public access and could facilitate the culture of defibrillation as required by the new Italian law proposal

Old Yellow Enzyme homologues in Mucor circinelloides: Expression profile and biotransformation

Abstract The reduction of C=C double bond, a key reaction in organic synthesis, is mostly achieved by traditional chemical methods. Therefore, the search for enzymes capable of performing this reaction is rapidly increasing. Old Yellow Enzymes (OYEs) are flavin-dependent oxidoreductases, initially isolated from Saccharomyces pastorianus. In this study, the presence and activation of putative OYE enzymes was investigated in the filamentous fungus Mucor circinelloides, which was previously found to mediate C=C reduction. Following an in silico approach, using S. pastorianus OYE1 amminoacidic sequence as template, ten putative genes were identified in the genome of M. circinelloides. A phylogenetic analysis revealed a high homology of McOYE1-9 with OYE1-like proteins while McOYE10 showed similarity with thermophilic-like OYEs. The activation of mcoyes was evaluated during the transformation of three different model substrates. Cyclohexenone, α-methylcinnamaldehyde and methyl cinnamate were completely reduced in few hours and the induction of gene expression, assessed by qRT-PCR, was generally fast, suggesting a substrate-dependent activation. Eight genes were activated in the tested conditions suggesting that they may encode for active OYEs. Their expression over time correlated with C=C double bond reduction

ANCA-associated vasculitis in childhood: Recent advances

Abstract Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides are rare systemic diseases that usually occur in adulthood. They comprise granulomatosis with polyangiitis (GPA, Wegener’s), microscopic polyangiitis (MPA) and eosinophilic granulomatosis with polyangiitis (EGPA, Churg-Strauss syndrome). Their clinical presentation is often heterogeneous, with frequent involvement of the respiratory tract, the kidney, the skin and the joints. ANCA-associated vasculitis is rare in childhood but North-American and European cohort studies performed during the last decade have clarified their phenotype, patterns of renal involvement and their prognostic implications, and outcome. Herein, we review the main clinical and therapeutic aspects of childhood-onset ANCA-associated vasculitis, and provide preliminary data on demographic characteristics and organ manifestations of an Italian multicentre cohort

Correlation between olfactory function, age, sex, and cognitive reserve index in the Italian population

Purpose: Loss of smell decreases the quality of life and contributes to the failure in recognizing hazardous substances. Given the relevance of olfaction in daily life, it is important to recognize an undiagnosed olfactory dysfunction to prevent these possible complications. Up to now, the prevalence of smell disorders in Italy is unknown due to a lack of epidemiological studies. Hence, the primary aim of this study was to evaluate the prevalence of olfactory dysfunction in a sample of Italian adults. Methods: Six hundred and thirty-three participants (347 woman and 286 men; mean age 44.9 years, SD 17.3, age range 18-86) were recruited from 10 distinct Italian regions. Participants were recruited using a convenience sapling and were divided into six different age groups: 18-29 years (N = 157), 30-39 years (N = 129), 40-49 years (N = 99), 50-59 years (N = 106), > 60 years (N = 142). Olfactory function, cognitive abilities, cognitive reserve, and depression were assessed, respectively, with: Sniffin' Sticks 16-item Odor Identification Test, Montreal Cognitive Assessment, Cognitive Reserve Index, and the Beck Depression Inventory. Additionally, socio-demographic data, medical history, and health-related lifestyle information were collected. Results: About 27% of participants showed an odor identification score < 12 indicating hyposmia. Multiple regression analysis revealed that OI was significantly correlated with age, sex, and cognitive reserve index, and young women with high cognitive reserve index showing the highest olfactory scores. Conclusion: This study provides data on the prevalence of olfactory dysfunction in different Italian regions

Development of a Nomogram Predicting the Risk of Persistence/Recurrence of Cervical Dysplasia

Background: Cervical dysplasia persistence/recurrence has a great impact on women's health and quality of life. In this study, we investigated whether a prognostic nomogram may improve risk assessment after primary conization. Methods: This is a retrospective multi-institutional study based on charts of consecutive patients undergoing conization between 1 January 2010 and 31 December 2014. A nomogram assessing the importance of different variables was built. A cohort of patients treated between 1 January 2015 and 30 June 2016 was used to validate the nomogram. Results: A total of 2966 patients undergoing primary conization were analyzed. The median (range) patient age was 40 (18-89) years. At 5-year of follow-up, 6% of patients (175/2966) had developed a persistent/recurrent cervical dysplasia. Median (range) recurrence-free survival was 18 (5-52) months. Diagnosis of CIN3, presence of HR-HPV types, positive endocervical margins, HPV persistence, and the omission of HPV vaccination after conization increased significantly and independently of the risk of developing cervical dysplasia persistence/recurrence. A nomogram weighting the impact of all variables was built with a C-Index of 0.809. A dataset of 549 patients was used to validate the nomogram, with a C-index of 0.809. Conclusions: The present nomogram represents a useful tool for counseling women about their risk of persistence/recurrence after primary conization. HPV vaccination after conization is associated with a reduced risk of CIN2+