University of Perugia

About: University of Perugia is a education organization based out in Perugia, Umbria, Italy. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 13365 authors who have published 39516 publications receiving 1265601 citations. The organization is also known as: Universitá degli Studi di Perugia & Universita degli Studi di Perugia.

Prognostic value of troponins in acute pulmonary embolism: a meta-analysis.

Abstract: Background— Whether elevated serum troponin levels identify patients with acute pulmonary embolism at high risk of short-term mortality or adverse outcome is undefined. Methods and Results— We perf...

Fermi Observations of High-Energy Gamma-Ray Emission from GRB 080916C

Abstract: Gamma-ray bursts (GRBs) are highly energetic explosions signaling the death of massive stars in distant galaxies. The Gamma-ray Burst Monitor and Large Area Telescope onboard the Fermi Observatory together record GRBs over a broad energy range spanning about 7 decades of gamma-ray energy. In September 2008, Fermi observed the exceptionally luminous GRB 080916C, with the largest apparent energy release yet measured. The high-energy gamma rays are observed to start later and persist longer than the lower energy photons. A simple spectral form fits the entire GRB spectrum, providing strong constraints on emission models. The known distance of the burst enables placing lower limits on the bulk Lorentz factor of the outflow and on the quantum gravity mass.

Comparing Media Systems

Abstract: In this chapter we propose a framework for comparing media systems. We propose, specifically, four major dimensions according to which media systems in Western Europe and North America can usefully be compared: (1) the development of media markets, with particular emphasis on the strong or weak development of a mass circulation press; (2) political parallelism; that is, the degree and nature of the links between the media and political parties or, more broadly, the extent to which the media system reflects the major political divisions in society; (3) the development of journalistic professionalism; and (4) the degree and nature of state intervention in the media system. Note that each of these can be seen in some sense as a single, quantitative dimension. That is, we can speak about high or low levels of press circulation, political parallelism, journalistic professionalism, or state intervention. But we shall also see that each of these dimensions is complex and that many more subtle qualitative distinctions become important as we begin to analyze concrete media systems. In many cases we will also introduce related, minor dimensions along which media systems may vary. Ours is not, of course, the first attempt to set forth a framework of this sort. We have tried to build on previous work, refining it based on our attempt to make sense of the patterns of difference and similarity we have found among the countries covered here, and to link these patterns to the social and political context in which they evolved.

Measurement of Separate Cosmic-Ray Electron and Positron Spectra with the Fermi Large Area Telescope

Abstract: We measured separate cosmic-ray electron and positron spectra with the Fermi Large Area Telescope. Because the instrument does not have an onboard magnet, we distinguish the two species by exploiting the Earth's shadow, which is offset in opposite directions for opposite charges due to the Earth's magnetic field. We estimate and subtract the cosmic-ray proton background using two different methods that produce consistent results. We report the electron-only spectrum, the positron-only spectrum, and the positron fraction between 20 GeV and 200 GeV. We confirm that the fraction rises with energy in the 20--100 GeV range and determine for the first time that it continues to rise between 100 and 200 GeV.