University of Catania

About: University of Catania is a education organization based out in Catania, Italy. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 14599 authors who have published 41195 publications receiving 1032705 citations. The organization is also known as: Università degli Studi di Catania & Universita degli Studi di Catania.

An Indication of Anisotropy in Arrival Directions of Ultra-high-energy Cosmic Rays through Comparison to the Flux Pattern of Extragalactic Gamma-Ray Sources

Abstract: A new analysis of the data set from the Pierre Auger Observatory provides evidence for anisotropy in the arrival directions of ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative of excess arrivals from strong, nearby sources. The data consist of 5514 events above 20 EeV with zenith angles up to 80 recorded before 2017 April 30. Sky models have been created for two distinct populations of extragalactic gamma-ray emitters: active galactic nuclei from the second catalog of hard Fermi-LAT sources (2FHL) and starburst galaxies from a sample that was examined with Fermi-LAT. Flux-limited samples, which include all types of galaxies from the Swift-BAT and 2MASS surveys, have been investigated for comparison. The sky model of cosmic-ray density constructed using each catalog has two free parameters, the fraction of events correlating with astrophysical objects, and an angular scale characterizing the clustering of cosmic rays around extragalactic sources. A maximum-likelihood ratio test is used to evaluate the best values of these parameters and to quantify the strength of each model by contrast with isotropy. It is found that the starburst model fits the data better than the hypothesis of isotropy with a statistical significance of 4.0σ, the highest value of the test statistic being for energies above 39 EeV. The three alternative models are favored against isotropy with 2.7σ-3.2σ significance. The origin of the indicated deviation from isotropy is examined and prospects for more sensitive future studies are discussed.

Measuring Hall Viscosity of Graphene’s Electron Fluid

Abstract: An electrical conductor subjected to a magnetic field exhibits the Hall effect in the presence of current flow. Here, we report a qualitative deviation from the standard behavior in electron systems with high viscosity. We found that the viscous electron fluid in graphene responds to nonquantizing magnetic fields by producing an electric field opposite to that generated by the ordinary Hall effect. The viscous contribution is substantial and identified by studying local voltages that arise in the vicinity of current-injecting contacts. We analyzed the anomaly over a wide range of temperatures and carrier densities and extracted the Hall viscosity, a dissipationless transport coefficient that was long identified theoretically but remained elusive in experiments.

Anxiety and depression in patients with endometriosis: impact and management challenges.

Abstract: Endometriosis is one of the most common gynecological diseases and affects ~10% of women in reproductive age The most common clinical signs of endometriosis are menstrual irregularities, chronic pelvic pain (CPP), dysmenorrhea, dyspareunia and infertility Symptoms of endometriosis often affect psychological and social functioning of patients For this reason, endometriosis is considered as a disabling condition that may significantly compromise social relationships, sexuality and mental health Considering this point, the aim of this narrative review is to elucidate the impact of anxiety and depression in the management of women with endometriosis Psychological factors have an important role in determining the severity of symptoms, and women who suffer from endometriosis report high levels of anxiety, depression and other psychiatric disorders In addition, endometriosis is one of the most important causes of CPP; women with endometriosis suffer from a wide range of pelvic pain such as dysmenorrhea, dyspareunia, nonmenstrual (chronic) pelvic pain, pain at ovulation, dyschezia and dysuria Several studies have underlined the influence of CPP on quality of life and psychological well-being of women with endometriosis Data suggest that the experience of pelvic pain is an important component of endometriosis and may significantly affect emotive functioning of affected women It has been demonstrated that high levels of anxiety and depression can amplify the severity of pain Further studies are needed to better understand the relationship between psychological factors and perception of pain Treatment of endometriosis may be hormonal or surgical Surgery is the primary treatment for more severe forms of endometriosis There are few data in the literature about the influence of psychological factors and psychiatric comorbidities on the effectiveness of treatments It is important to evaluate the presence of previous psychiatric diseases in order to select the most appropriate treatment for the patient

Highly conductive ∼40-nm-long molecular wires assembled by stepwise incorporation of metal centres

Abstract: A long-standing problem with molecular wires is their poor transport properties. Highly conductive and very long wires have now been synthesized by incorporating metal centres into rigid molecular backbones, which shows promise for their use in electronic devices. One of the main goals of molecular electronics is to achieve electronic functions from devices consisting of tailored organic molecules connecting two metal electrodes. The fabrication of nanometre-scale spaced electrodes still results in expensive, and often scarcely reproducible, devices1,2,3,4. On the other hand, the ‘conductance’ of long organic molecules—generally dominated by the tunnelling mechanism—is very poor5,6,7,8,9. Here, we show that by incorporating a large number of metal centres into rigid molecular backbones we can obtain very long (up to 40 nm) and highly ‘conductive’ molecular wires. The metal-centre molecular wires are assembled in situ on metal surfaces via a sequential stepwise coordination of metal ions by terpyridine-based ligands10,11. They form highly ordered molecular films of elevated mechanical robustness. The electrical properties, characterized by a junction based on Hg electrodes5,6, indicate that the ‘conductance’ of these metal-centre molecular wires does not decrease significantly even for very long molecular wires, and depends on the nature of the incorporated redox centre. The outstanding electrical and mechanical characteristics of these easy-to-assemble molecular systems open the door to a new generation of molecular wires, able to bridge large-gap electrodes, and to form robust films for organic electronics.