20 research outputs found

    Assessing systemic risk due to fire sales spillover through maximum entropy network reconstruction

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    Assessing systemic risk in financial markets is of great importance but it often requires data that are unavailable or available at a very low frequency. For this reason, systemic risk assessment with partial information is potentially very useful for regulators and other stakeholders. In this paper we consider systemic risk due to fire sales spillover and portfolio rebalancing by using the risk metrics defined by Greenwood et al. (2015). By using the Maximum Entropy principle we propose a method to assess aggregated and single bank's systemicness and vulnerability and to statistically test for a change in these variables when only the information on the size of each bank and the capitalization of the investment assets are available. We prove the effectiveness of our method on 2001-2013 quarterly data of US banks for which portfolio composition is available.Comment: 36 pages, 6 figures, Accepted on Journal of Economic Dynamics and Contro

    Anxiety is Prevailing in Non-Cardiac Chest Pain Subjects, while Somatisation is Not A Comparative Study in the Emergency Department

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    Objective: The main purpose of this study was to verify if non-cardiac chest pain (NCCP) subjects recruited in an Emergency Department were more anxious, depressive or burdened by somatoform symptoms as compared with cardiac chest pain (CCP) subjects, and with subjects without chest pain (WOCP). Methods: We included patients with chest pain not attributable to a gastro-oesophageal reflux disorder. NCCP subjects were negative at ECG examination and at troponin test at baseline and after three months. A number of instruments were administered, measuring anxiety and depression (HADS), somatisation (somatisation scale of SCL- 90, TAS-20), and the health-related QoL (SF-12), along with other scales measuring the social and experiential profile. Results: We recruited 435 subjects (of which NCCP were 44.8%) in the Emergency Department, while other 147 subjects were recruited in a primary care clinic. The logistic regression showed that the levels of HADS anxiety in the three groups were dissimilar, even when adjusted for confounding variables: taking NCCP as reference category, adjusted ORs were 0.64 for CCP (IC95% 0.42 \u2013 0.96) and 0.23 for WOCP (IC95% 0.13 \u2013 0.40). When considering the somatisation construct, CCP and NCCP subjects reported similar somatic symptom complaints, higher than WOCP subjects. Moreover, even if NCCP subjects showed higher TAS-20 scores than WOCP subjects, these scores were below the range of a possible alexithymia. As for the physical health-related QoL (SF-12, subscale PCS-12), regression analyses showed that the PCS-12 mean score of NCCP was higher than that of CCP ( f -2.31; IC95% -4.14 to -0.48) and lower than that of WOCP ( f 2.24; IC95% 0.12 \u2013 4.37). Conclusion : NCCP subjects are characterised from an elevated anxiety, together with a better physical well-being, when compared with subjects who have a cardiac failure. The somatisation construct seems less useful to distinguish NCCP from CCP subjects. Consequently, anxiety should be the major target of our mental-health intervention when treating subjects with chest pain

    Modelling time-varying interactions in complex systems: the Score Driven Kinetic Ising Model

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    A common issue when analyzing real-world complex systems is that the interactions between their elements often change over time. Here we propose a new modeling approach for time-varying interactions generalising the well-known Kinetic Ising Model, a minimalistic pairwise constant interactions model which has found applications in several scientific disciplines. Keeping arbitrary choices of dynamics to a minimum and seeking information theoretical optimality, the Score-Driven methodology allows to extract from data and interpret the presence of temporal patterns describing time-varying interactions. We identify a parameter whose value at a given time can be directly associated with the local predictability of the dynamics and we introduce a method to dynamically learn its value from the data, without specifying parametrically the system's dynamics. We extend our framework to disentangle different sources (e.g. endogenous vs exogenous) of predictability in real time, and show how our methodology applies to a variety of complex systems such as financial markets, temporal (social) networks, and neuronal populations

    Hepatocellular Carcinoma in HIV-infected Patients: Check Ealy, Treat Hard

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    Purpose. Hepatocellular carcinoma (HCC) is an increasingcause of mortality in HIV-infected patients inthe highly active antiretroviral therapy (HAART) era.The aims of this study were to describe HCC tumorcharacteristics and different therapeutic approaches, toevaluate patient survival time from HCC diagnosis, andto identify clinical prognostic predictors in patients withand without HIV infection.Patients and Methods. A multicenter observationalretrospective comparison of 104 HIV-infected patientsand 484 uninfected patients was performed in four Italiancenters. HCC was staged according to the BarcelonaClinic Liver Cancer (BCLC) criteria.Results. Tumor characteristics of patients with andwithout HIV were significantly different for age, EasternCooperative Oncology Group performance status(PS) score <1, and etiology of chronic liver disease. Despitethe similar potentially curative option rate and better BCLC stage at diagnosis, the median survivaltime was significantly shorter in HIV patients. HIVpatients were less frequently retreated at relapse.Independent predictors of survival were: BCLC stage,potentially effective HCC therapy, tumor dimension <3cm, HCC diagnosis under a screening program, HCC recurrence,and portal vein thrombosis. Restricting the analysisto HIV patients only, all positive prognostic factorswere confirmed together with HAART exposure.Conclusion. This study confirms a significantlyshorter survival time in HIV HCC patients. The lessaggressive retreatment at recurrence approach does notbalance the benefit of younger age and better BCLCstage and PS score of HIV patients. Thus, consideringthe prognosis of HIV HCC patients, effective screeningtechniques, programs, and specific managementguidelines are urgently needed

    Embracing open innovation to acquire external ideas and technologies and to transfer internal ideas and technologies outside

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    The objective of this dissertation is to increase understanding of how organizations can embrace open innovation in order to acquire external ideas and technologies from outside the organization, and to transfer internal ideas and technologies to outside the organization. The objective encompasses six sub-objectives, each addressed in one or more substudies. Altogether, the dissertation consists of nine substudies and a compendium summarizing the substudies. An extensive literature review was conducted on open innovation and crowdsourcing literature (substudies 1–4). In the subsequent empirical substudies, both qualitative research methods (substudies 5–7) and quantitative research methods (substudies 8–9) were applied. The four literature review substudies provided insights on the body of knowledge on open innovation and crowdsourcing. These substudies unveiled most of the influential articles, authors, and journals of open innovation and crowdsourcing disciplines. Moreover, they identified research gaps in the current literature. The empirical substudies offer several insightful findings. Substudy 5 shows how non-core ideas and technologies of a large firm can become valuable, especially for small firms. Intermediary platforms can find solutions to many pressing problems of large organizations by engaging renowned scientists from all over world (substudy 6). Intermediary platforms can also bring breakthrough innovations with novel mechanisms (substudy 7). Large firms are not only able to garner ideas by engaging their customers through crowdsourcing but they can also build long-lasting relations with their customers (substudies 8 and 9). Embracing open innovation brings challenges for firms too. Firms need to change their organizational structures in order to be able to fully benefit from open innovation. When crowdsourcing is successful, it produces a very large number of new ideas. This has the consequence that firms need to allocate a significant amount of resources in order to identify the most promising ideas. In an idea contest, customarily, only one or a few best ideas are rewarded (substudy 7). Sometimes, no reward is provided for the selected idea (substudies 8 and 9). Most of the ideas that are received are not implemented in practice

    Lavorare in comunicazione: soddisfatti e poco rimborsati

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    The paper focus on the data analysis of a survey about the occupational situation of young people that are graduated in communication studies at the University of Rome La Sapienza. In particular we highlight the relationship among occupational conditions, levels of satisfaction and professional ambitions

    CD103 Expression on Regulatory and Follicular T Cells in Lymph Nodes, Bronchoalveolar Lavage Fluid and Peripheral Blood of Sarcoidosis Patients

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    (1) Background: Sarcoidosis is a chronic multisystem disorder of unknown aetiology, driven by a T-cell mechanism allowing T-cell attachment and transmigration through the endothelium, and endorsed by the expression of an integrin alpha-E beta-7 (CD103). This study aimed to analyse the different distribution and compartmentalisation of CD103 expression on T cell subsets in BAL, peripheral blood mononuclear cells (PBMC) and lymph nodes (LLN) from sarcoidosis patients. (2) Patients: We consecutively and prospectively enrolled 14 sarcoidosis patients. We collected PBMC, LLN and BAL at the same time from all patients. Through flow cytometric analysis, we analysed the expression of CD103 on regulatory and follicular T cell subsets. (3) Results: All patients were in radiological Scadding stage II. The multivariate analysis found that the variables which most influenced the peripheral blood compartment were high CD8+ and low ThReg, CD8+CD103+ and Tfh cell percentages. A principal component analysis plot performed to distinguish LLN, BAL and PBMC showed that they separated on the basis of CD4+, CD4+CD103+, CD8+, CD8+CD103+, TcEffector, TcNaive, ThNaive, ThEffector, Threg, ThregCD103+, Tfh, TcfCXC5+ and CD4+CD103+/CD4+ with 65.96% of the total variance. (4) Conclusions: Our study is the first to report a link between the imbalance in circulating, alveolar and lymph node CD8+ and CD8+CD103+ T cells, ThReg, Tfh and ThNaive and the CD103+CD4+/CD4+ T cell ratio in the development of sarcoidosis. These findings shine a spotlight on the pathogenesis of sarcoidosis and may offer new predictors for diagnosis. Our study provides additional understanding for a personalised, and hopefully more effective treatment of sarcoidosis
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