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Institution

University of Perugia

EducationPerugia, Umbria, Italy
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.


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Journal ArticleDOI
TL;DR: The results support early activation of the l-arginine/NO pathway which accompanies the release of vasoactive peptides from trigeminal endings and a late rise in the synthesis of prostanoids with algogenic and vaso active properties which may intervene in maintaining the headache phase.
Abstract: Despite evidence emerging from the experimental model of nitroglycerin-induced headache, the endogenous increase in nitric oxide (NO) production during migraine attacks is only speculative It has been hypothesized that there is a close relationship between activation of the L-arginine/NO pathway and production of certain vasoactive and algogenic prostaglandins during spontaneous migraine attacks, but this suggestion also needs to be confirmed In the present study the levels of nitrites, the stable metabolites of NO, were determined with high performance liquid chromatography (HPLC) in the internal jugular venous blood of five patients affected by migraine without aura examined ictally These samples were taken within 30 min, 1, 2, and 4 h from the onset of the attack and at the end of the ictal period At the same time, the plasma levels of calcitonin gene-related peptide (CGRP), neurokinin A (NKA), prostaglandin E2 (PGE2) and 6 keto PGF1alpha, the stable product of PGI2, were assessed with radioimmunoassay (RIA) kits in the same samples The levels of the intracellular messengers, cGMP and cAMP, were also measured with the RIA method Nitrite, cGMP, CGRP and NKA levels reached their highest values at the first hour, then they tended to decrease progressively and returned, after the end of attacks, to values similar or below those detected at the time of catheter insertion (ANOVA, statistical significance: P<0001; P<<0002; P<0002; P<0003, respectively) PGE2 and 6 keto PGF1alpha, as well as cAMP levels also significantly increased at the first hour but reached a peak at the 2nd hour and remained in the same range until the 4th and 6th hours Then their values tended to decrease after the end of attacks, becoming lower than those measured immediately after catheter positioning for internal jugular venous blood drawing (ANOVA: P<0002, P<0004, P<0001, respectively) Our results support early activation of the L-arginine/NO pathway which accompanies the release of vasoactive peptides from trigeminal endings and a late rise in the synthesis of prostanoids with algogenic and vasoactive properties which may intervene in maintaining the headache phase

239 citations

Journal ArticleDOI
Markus Ackermann, Marco Ajello1, Alice Allafort2, W. B. Atwood3  +188 moreInstitutions (45)
TL;DR: The first Fermi-LAT catalog of >10GeV sources (1FHL) has 514 sources as discussed by the authors, of which 449 (87%) could be associated with known sources, of which 393 (76% of the 1FHL sources) are active galactic nuclei.
Abstract: We present a catalog of gamma-ray sources at energies above 10 GeV based on data from the Large Area Telescope (LAT) accumulated during the first three years of the Fermi Gamma-ray Space Telescope mission. The first Fermi-LAT catalog of >10GeV sources (1FHL) has 514 sources. For each source we present location, spectrum, a measure of variability, and associations with cataloged sources at other wavelengths. We found that 449 (87%) could be associated with known sources, of which 393 (76% of the 1FHL sources) are active galactic nuclei. Of the 27 sources associated with known pulsars, we find 20 (12) to have significant pulsations in the range >10GeV (>25GeV). In this work we also report that, at energies above 10 GeV, unresolved sources account for 27+/-8 % of the isotropic gamma-ray background, while the unresolved Galactic population contributes only at the few percent level to the Galactic diffuse background. We also highlight the subset of the 1FHL sources that are best candidates for detection at energies above 50-100 GeV with current and future ground-based gamma-ray observatories.

239 citations

Journal ArticleDOI
P. Perucci1
TL;DR: In this paper, changes in enzyme activity levels, in biomass-C content, and in the rate of fluorescein diacetate hydrolysis were measured in a loamy soil to which solid municipal refuse had been applied as compost over a 3-year period at two different rates.
Abstract: Changes in enzyme activity levels, in biomass-C content, and in the rate of fluorescein diacetate hydrolysis were measured in a loamy soil to which solid municipal refuse had been applied as compost over a 3-year period at two different rates. Addition of the compost caused significant increases in the activity of all enzymes tested. The increases were much higher at 90 t ha-1 year-1 than at 30 t ha-1 year-1. Significant increases were also observed in the biomass-C content and in the rate of fluorescein diacetate hydrolysis. Significant correlations among changes in biomass-C content and the rate of fluorescein diacetate hydrolysis and the changes in all enzymes tested were found. Two activity indices were calculated; a biological index of fertility and an enzyme activity number. No correlations were found between the biological index of fertility and the changes in the various enzyme activities. However, significant correlations were found either between enzyme activity number and most of the changes in enzyme activity, or between the enzyme activity number index and the biomass-C content (r=0.850). The use of a new activity index, the hydrolysis coefficient, is proposed. This coefficient was significantly correlated with biomass-C content (r=0.925) and with the enzyme activity number index (r=0.780).

239 citations

Journal ArticleDOI
TL;DR: In this article, the extent to which social structures and social legitimization influence ESG disclosure practices and each pillar was investigated using a cross-country sample of 14,174 firm-year observations during 2005-2012.
Abstract: In recent years, companies receive pressure to release environmental, social, and governance (ESG) disclosure, since these are perceived as critical issues by society. Despite this pressure, ESG disclosure practices considerably vary by firm. Prior academic literature investigated country- and firm-level factors determining such variation, alternatively adopting the institutional and legitimacy theory. By combining these theories in a unique framework, this study investigates the extent to which social structures (i.e., institutional theory) and social legitimization (i.e., legitimacy theory) influence ESG disclosure practices and each pillar. Results obtained using a cross-country sample of 14,174 firm-year observations during 2005–2012 provide evidence that country-level characteristics such as a political system (legal framework and corruption), labor system (labor protection and unemployment rate), and cultural system (Social Cohesion and Equal Opportunities) significantly affect firms’ ESG disclosure practices. However, their impact is heterogeneous in that they either reduce or enhance disclosure levels and may differ by pillar. Results for firm-level characteristics related to a firm’s visibility (analysts coverage, cross-listing, leverage, and size) demonstrate a positive and homogeneous effect on ESG disclosure and each pillar. These results inform policy makers and regulators aiming to enhance ESG disclosure levels of the risk they incur when managing variables related to social structure and the benefits of exposing firms to higher visibility.

239 citations

Journal ArticleDOI
TL;DR: The feasibility of performing tractography on the group-averaged DT-MRI data set is investigated and the possibility and implications of generating a generic map of brain connectivity from a group of subjects is considered.

239 citations


Authors

Showing all 13488 results

NameH-indexPapersCitations
Michael Grätzel2481423303599
Luigi Ferrucci1931601181199
Tobin J. Marks1591621111604
Johan Auwerx15865395779
Tony Pawson15042585196
Jack Hirsh14673486332
Alexander Belyaev1421895100796
R. L. McCarthy1411238115696
Harvey B Newman139159488308
Guido Tonelli138145897248
Elias Campo13576185160
Alberto Messineo134151196492
Franco Ligabue134140495389
Roberto Tenchini133139094541
R. Bartoldus132162497405
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023108
2022226
20212,487
20202,594
20192,362
20182,274