University of Palermo

About: University of Palermo is a education organization based out in Palermo, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 15621 authors who have published 40250 publications receiving 964384 citations. The organization is also known as: Università degli Studi di Palermo & Universita degli Studi di Palermo.

Sovereign Credit Ratings and Financial Markets Linkages: Application to European Data

Abstract: We use EU sovereign bond yield and CDS spreads daily data to carry out an event study analysis on the reaction of government yield spreads before and after announcements from rating agencies (Standard & Poor’s, Moody’s, Fitch). Our results show: significant responses of government bond yield spreads to changes in rating notations and outlook, particularly in the case of negative announcements; announcements are not anticipated at 1-2 months horizon but there is bi-directional causality between ratings and spreads within 1-2 weeks; spillover effects especially from lower rated countries to higher rated countries; and persistence effects for recently downgraded countries.

Competing risks and prognostic stages of cirrhosis: A 25-year inception cohort study of 494 patients

Abstract: Summary Background Morphological, haemodynamic and clinical stages of cirrhosis have been proposed, although no definite staging system is yet accepted for clinical practice. Aim To investigate whether clinical complications of cirrhosis may define different prognostic disease stages. Methods Analysis of the database from a prospective inception cohort of 494 patients. Decompensation was defined by ascites, bleeding, jaundice or encephalopathy. Explored potential prognostic stages: 1, compensated cirrhosis without oesophago-gastric varices; 2, compensated cirrhosis with varices; 3, bleeding without other complications; 4, first nonbleeding decompensation; 5, any second decompensating event. Patient flow across stages was assessed by a competing risks analysis. Results Major patient characteristics were: 199 females, 295 males, 404 HCV+, 377 compensated, 117 decompensated cirrhosis. The mean follow-up was 145 ± 109 months without dropouts. Major events: 380 deaths, 326 oesophago-gastric varices, 283 ascites, 158 bleeding, 146 encephalopathy, 113 jaundice, 126 hepatocellular carcinoma and 19 liver transplantation. Patients entering each prognostic stage along the disease course were: 202, stage 1; 216, stage 2; 75 stage 3; 206 stage 4; 213 stage 5. Five-year transition rate towards a different stage, for stages 1–4 was 34.5%, 42%, 65% and 78%, respectively (P < 0.0001); 5-year mortality for stages 1–5 was 1.5%, 10%, 20%, 30% and 88% respectively (P < 0.0001). An exploratory analysis showed that this patient stratification may configure a prognostic system independent of the Child–Pugh score, Model for End Stage Liver Disease and comorbidity. Conclusion The development of oesophago-gastric varices and decompensating events in cirrhosis identify five prognostic stages with significantly increasing mortality risks.

A Typical Immune T/B Subset Profile Characterizes Bicuspid Aortic Valve: In an Old Status?

Abstract: Bicuspid valve disease is associated with the development of thoracic aortic aneurysm. The molecular mechanisms underlying this association still need to be clarified. Here, we evaluated the circulating levels of T and B lymphocyte subsets associated with the development of vascular diseases in patients with bicuspid aortic valve or tricuspid aortic valve with and without thoracic aortic aneurysm. We unveiled that the circulating levels of the MAIT, CD4+IL−17A+, and NKT T cell subsets were significantly reduced in bicuspid valve disease cases, when compared to tricuspid aortic valve cases in either the presence or the absence of thoracic aortic aneurysm. Among patients with tricuspid aortic valve, these cells were higher in those also affected by thoracic aortic aneurysm. Similar data were obtained by examining CD19+ B cells, naive B cells (IgD+CD27−), memory unswitched B cells (IgD+CD27+), memory switched B cells (IgD−CD27+), and double-negative B cells (DN) (IgD−CD27−). These cells resulted to be lower in subjects with bicuspid valve disease with respect to patients with tricuspid aortic valve. In whole, our data indicate that patients with bicuspid valve disease show a quantitative reduction of T and B lymphocyte cell subsets. Future studies are encouraged to understand the molecular mechanisms underlying this observation and its pathophysiological significance.

Evolving mobile robots in simulated and real environments

Abstract: The problem of the validity of simulation is particularly relevant for methodologies that use machine learning techniques to develop control systems for autonomous robots, as, for instance, the artificial life approach known as evolutionary robotics. In fact, although it has been demonstrated that training or evolving robots in real environments is possible, the number of trials needed to test the system discourages the use of physical robots during the training period. By evolving neural controllers for a Khepera robot in computer simulations and then transferring the agents obtained to the real environment we show that (a) an accurate model of a particular robot-environment dynamics can be built by sampling the real world through the sensors and the actuators of the robot; (b) the performance gap between the obtained behaviors in simulated and real environments may be significantly reduced by introducing a "conservative" form of noise; (c) if a decrease in performance is observed when the system is transferred to a real environment, successful and robust results can be obtained by continuing the evolutionary process in the real environment for a few generations.