88 research outputs found

    Portfolio of compositions

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    This text contains a short general description of my experience at the University of Birmingham. This is an attempt to communicate how my perception in composing music has changed and evolved. The focus is to introduce briefly my experience before I arrived at the University of Birmingham, then go through all the compositions I have worked on during my PhD programme. This attempt is to explain the main processes I have used for composing, giving a wider view of the issues that I was interested in developing. Furthermore, I will consider some technical aspects with reference to facilities that the University of Birmingham offers to students. This appears to be the right opportunity for them to explore technology almost without any restrictions. I also give some information about other nonmusical issues, which I was interested in developing in order to look into personal aesthetic directions. My main reason for being at the University of Birmingham was to explore compositional processes different from my previous experiences, in order to enlarge my abilities and perspectives in music composition

    Essays on Stochastic Orderings in Portfolio Selection

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    Stochastic Ordering represents a relevant approach in portfolio selection for various reasons. Firstly, stochastic ordering is theoretically justified by expected utility theory. Typically, investors are classified according to their attitude towards risk. For each class of investors then, it is possible to define stochastic orderings coherent with their risk preference. Secondly, stochastic ordering is flexible enough to allow different definitions of efficiency suitable for each category of investors. This thesis proposes several applications of stochastic ordering to portfolio selection problems. In the first chapter, an analysis of the relationship between second order stochastic dominance efficient sets and the mean variance efficient frontier is proposed. Not only do the two sets differ under many aspects, but the global minimum variance portfolio and other mean variance efficient portfolios are dominated in the sense of second order stochastic dominance. Based on this fact, the chapter proposes some dominating strategies that are able to outperform the global minimum variance portfolio. In the second chapter, starting from recent findings in the literature, that address the behavior of investors as neither non-satiable, nor risk averse or risk seeking, an extension of the classic definition of stochastic dominance efficiency linked to behavioral finance is given. In particular, investors' behavior changes according to market conditions. The last part of the chapter presents a methodology, based on estimation function theory, that allows to test for portfolio efficiency with respect to a general stochastic ordering. Both the analysis of efficiency for second order of stochastic dominance and behavioral finance, questions the validity of highly diversified choices. For this reason, this thesis continues the analysis by introducing risk diversification measures, a new class of functional quantifying the amount of idiosyncratic risk diversified among the assets in a portfolio. The mean risk diversification efficient frontier is introduced, along with the concept of mean risk diversification efficiency. The empirical analysis describes the relationship between risk aversion, risk diversification and classic diversification, and shows how risk diversification based strategies perform under periods of financial distress

    Essays on Stochastic Orderings in Portfolio Selection

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    Stochastic Orderings represent a relevant approach in portfolio selection for various reasons. Firstly, Stochastic Ordering are theoretically justified by Expected Utility theory. Typically, investors are classified according to their attitude toward risk. For each class of investors then, it is possible to define stochastic orderings coherent with investors' preference. Secondly, Stochastic Orderings are flexible enough to allow different definitions of efficiency suitable for each category of investors. This Thesis proposes several applications of Stochastic Orderings to portfolio selection problems. In the first chapter, an analysis of the relationship between Second order of Stochastic Dominance efficient set and Mean Variance Efficient Frontier is proposed. Not only the two sets differ under many aspects, but the Global Minimum Variance portfolio and other Mean Variance Efficient portfolios are dominated in the sense of Second order of Stochastic Dominance. Based on this fact, the chapter concludes proposing dominating strategies able to outperform the Global Minimum Variance portfolio. In the second chapter, starting from recent findings in the literature, that address the behavior of investors as non satiable, nor risk averting nor risk seeking, an extension of classic definition of Stochastic Dominance efficiency, linked to behavioral finance is given. In particular, investors' behavior changes according to market conditions. The last part of the chapter presents a methodology, based on estimation function theory, to test for portfolio efficiency with respect a general stochastic ordering. Both the analysis of efficiency for Second order of Stochastic Dominance and behavioral finance, questioned the validity of highly diversified choices. For this reason, this thesis concludes introducing Risk Diversification measures, a new class of functional quantifying the amount of idiosyncratic risk diversified among the assets in a portfolio. The Mean Risk Diversification Efficient Frontier is introduced, along with the concept of Mean Risk Diversification efficiency. The empirical analysis describes the relationship between risk aversion, Risk Diversification and classic diversification, and show how Risk Diversification based strategies perform under periods of financial distress

    Anisotropic compression in the high pressure regime of pure and Cr-doped vanadium dioxide

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    We present structural studies of V1−x_{1-x}Crx_xO2_2 (pure, 0.7% and 2.5% Cr doped) compounds at room temperature in a diamond anvil cell for pressures up to 20 GPa using synchrotron x-ray powder diffraction. All the samples studied show a persistence of the monoclinic M1M_1 symmetry between 4 and 12 GPa. Above 12 GPa, the monoclinic M1M_1 symmetry changes to isostructural MxM_x phase (space group P21/cP2_1/c) with a significant anisotropy in lattice compression of the bb-cc plane of the M1M_{1} phase. This behavior can be reconciled invoking the pressure induced charge-delocalization

    Backtesting AVaR and VaR with a simulated copula

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    The aim of this study is to verify whether the average value at risk (AVaR) can be a good alternative to the value at risk (VaR) for estimating portfolio losses, especially regarding tail events. To achieve this aim, we use a copula framework to estimate the dependence between the stock returns of a portfolio composed of 94 components of the S&P100 index to compute the AVaR and VaR and compare the results with respect to the Gaussian exponentially weighted moving average (EWMA). To compute the simulated returns, we employ the algorithm used by Biglova et al. (2014) in portfolio selection problems and then backtest the model with Kupiec’s and Christoffersen’s tests. The results are coherent with the literature; in particular, the VaR computed both via the copula and via the EWMA seems to fail to provide an accurate risk measurement while the AVaR with the copula and EWMA appears to be more reliable

    Optimal dynamic climate adaptation pathways: a case study of New York City

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    Assessing climate risk and its potential impacts on our cities and economies is of fundamental importance. Extreme weather events, such as hurricanes, floods, and storm surges can lead to catastrophic damages. We propose a flexible approach based on real options analysis and extreme value theory, which enables the selection of optimal adaptation pathways for a portfolio of climate adaptation projects. We model the severity of extreme sea level events using the block maxima approach from extreme value theory, and then develop a real options framework, factoring in climate change, sea level rise uncertainty, and the growth in asset exposure. We then apply the proposed framework to a real-world problem, considering sea level data as well as different adaptation investment options for New York City. Our research can assist governments and policy makers in taking informed decisions about optimal adaptation pathways and more specifically about reducing flood and storm surge risk in a dynamic settings.Comment: 29 pages, 5 figures, and 4 table

    Automatically extracted machine learning features from preoperative CT to early predict microvascular invasion in HCC: the role of the Zone of Transition (ZOT)

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    open12noMicrovascular invasion (MVI) is a consolidated predictor of hepatocellular carcinoma (HCC) recurrence after treatments. No reliable radiological imaging findings are available for preoperatively diagnosing MVI, despite some progresses of radiomic analysis. Furthermore, current MVI radiomic studies have not been designed for small HCC nodules, for which a plethora of treatments exists. This study aimed to identify radiomic MVI predictors in nodules ≤3.0 cm by analysing the zone of transition (ZOT), crossing tumour and peritumour, automatically detected to face the uncertainties of radiologist’s tumour segmentation. Methods: The study considered 117 patients imaged by contrast-enhanced computed tomography; 78 patients were finally enrolled in the radiomic analysis. Radiomic features were extracted from the tumour and the ZOT, detected using an adaptive procedure based on local image contrast variations. After data oversampling, a support vector machine classifier was developed and validated. Classifier performance was assessed using receiver operating characteristic (ROC) curve analysis and related metrics. Results: The original 89 HCC nodules (32 MVI+ and 57 MVI−) became 169 (62 MVI+ and 107 MVI−) after oversampling. Of the four features within the signature, three are ZOT heterogeneity measures regarding both arterial and venous phases. On the test set (19MVI+ and 33MVI−), the classifier predicts MVI+ with area under the curve of 0.86 (95%CI (0.70–0.93), p∼10^−5), sensitivity = 79% and specificity = 82%. The classifier showed negative and positive predictive values of 87% and 71%, respectively. Conclusions: The classifier showed the highest diagnostic performance in the literature, disclosing the role of ZOT heterogeneity in predicting the MVI+ status.noneMatteo Renzulli, Margherita Mottola, Francesca Coppola, Maria Adriana Cocozza, Silvia Malavasi, Arrigo Cattabriga, Giulio Vara, Matteo Ravaioli, Matteo Cescon, Francesco Vasuri, Rita Golfieri, Alessandro BevilacquaMatteo Renzulli, Margherita Mottola, Francesca Coppola, Maria Adriana Cocozza, Silvia Malavasi, Arrigo Cattabriga, Giulio Vara, Matteo Ravaioli, Matteo Cescon, Francesco Vasuri, Rita Golfieri, Alessandro Bevilacqu

    Cortisol, cortisone and DHEAS in epidermis and scales of fish Aphanius fasciatus: HPLC-MS/MS measurement of stress indicators as proxies for natural and human-induced factors

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    Fish health can be affected by a multitude of stressors. Acute and chronic stress assessment via specific hormones monitoring has become a trending research topic. Common investigated matrices are blood and plasma, but recently less invasive substrates have been identified. As chemical composition of skin mucus/epidermis has been demonstrated to link with acute stress, and of scales with chronic stress in fish, the aim of the study was firstly to improve the determination of three stress hormones, namely cortisol (COL), cortisone (CON), and dehydroepiandrosterone-3-sulfate (DHEAS), in skin mucus/epidermis and scales of Aphanius fasciatus. Secondly, an evaluation of the impact of different environments on hormones concentrations was carried out. A liquid chromatography coupled to tandem mass spectrometry method (HPLC-MS/MS) and a preanalytical procedure were validated to determine COL, CON and DHEAS. This methodology was applied to compare a pull of field-collected fish with a pull of fish housed in the laboratory for one year. Our results highlighted a significant presence of cortisol and cortisone in epidermis of the latter pull (averagely 0.10 and 0.14 ng mg−1, respectively), while in the first pull both hormones were much less concentrated (averagely 0.006 and 0.008 ng mg−1, respectively). Scales of both pulls showed presence of hormones, with a higher concentration for fish housed in the laboratory, although a relevant difference in concentration was found only for cortisone. DHEAS was always below the limit of detectio

    Curcumin-Based β-Diketo Ligands for Ga3+: Thermodynamic Investigation of Potential Metal-Based Drugs

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    Curcumin is known for its therapeutic properties; among these, antioxidant, anti-inflammatory and anti-cancer ones stand out. Besides, curcumin metal complexes have shown widespread application in medicine and can be exploited as lead structures for developing metal-based drugs. Unfortunately, curcumin is poorly bioavailable, mainly due to its instability in physiological conditions; this weakness is tightly connected to the presence of the β-diketo moiety undergoing tautomeric equilibrium. Stability and metal-chelating ability can be tuned by modulating the electronic effects and steric hindrance close to the β-diketo moiety; in addition, formation of a metal complex shifts the tautomeric equilibrium towards the β-keto–enol form and increases stability in biological media. Among the metals used in clinical therapy, gallium nitrate has shown to have significant antitumor activity against non-Hodgkin lymphoma and bladder cancer, thus indicating that gallium-based drugs have potential for further development as antineoplastic agents with improved therapeutic activity. Curcuminoids have demonstrated high affinity for gallium(III), allowing the formation of stable positively charged M:L 1:2 β-diketonate complexes that benefit from the therapeutic activity of both the metal and the ligand. Seven new curcumin derivatives were synthesized and completely characterized. The new derivatives retain the solvent-dependent keto–enol tautomerism, with the prevalence of the diketo form in aqueous solution. Enhanced stability in simulated physiological conditions was observed in comparison to the lead compound curcumin. The presence of Ga3+ anticipates the dissociation of the enolic proton, allowing chelate complex formation, and simultaneously it shifts the tautomeric equilibrium towards the keto–enol form. A complete 1H/13C NMR and UV–Vis study was performed to define the metal-to-ligand stoichiometry ratio and the overall stability constants. In addition, we demonstrated that some of the derivatives have increased antiproliferative activity on colon cancer cells compared to curcumin and antioxidant properties. On the whole, the synthesized curcumin-based molecules may act as new gallium(III) chelators with improved stability with respect to curcumin and could open interesting perspectives for the development of novel therapeutic agents for cancer

    DIGItal Health Literacy after COVID-19 Outbreak among Frail and Non-Frail Cardiology Patients: The DIGI-COVID Study

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    Background: Telemedicine requires either the use of digital tools or a minimum technological knowledge of the patients. Digital health literacy may influence the use of telemedicine in most patients, particularly those with frailty. We aimed to explore the association between frailty, the use of digital tools, and patients' digital health literacy. Methods: We prospectively enrolled patients referred to arrhythmia outpatient clinics of our cardiology department from March to September 2022. Patients were divided according to frailty status as defined by the Edmonton Frail Scale (EFS) into robust, pre-frail, and frail. The degree of digital health literacy was assessed through the Digital Health Literacy Instrument (DHLI), which explores seven digital skill categories measured by 21 self-report questions. Results: A total of 300 patients were enrolled (36.3% females, median age 75 (66-84)) and stratified according to frailty status as robust (EFS ≤ 5; 70.7%), pre-frail (EFS 6-7; 15.7%), and frail (EFS ≥ 8; 13.7%). Frail and pre-frail patients used digital tools less frequently and accessed the Internet less frequently compared to robust patients. In the logistic regression analysis, frail patients were significantly associated with the non-use of the Internet (adjusted odds ratio 2.58, 95% CI 1.92-5.61) compared to robust and pre-frail patients. Digital health literacy decreased as the level of frailty increased in all the digital domains examined. Conclusions: Frail patients are characterized by lower use of digital tools compared to robust patients, even though these patients would benefit the most from telemedicine. Digital skills were strongly influenced by frailty
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