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Lauzacco, Italy

Clericuzio M.,University of Piemonte Orientale | Cassino C.,University of Piemonte Orientale | Corana F.,DellUniversity Pavia | Vidari G.,University of Pavia
Phytochemistry | Year: 2012

Four aristolane sesquiterpenes were isolated from the fruiting bodies of Russula lepida and R. amarissima, namely (1R,2S)-1,2-dihydroxyaristolone (6), (2S,11S)-2,12-dihydroxy-aristolone (7), (1R,2S,11S)-1,2,12-trihydroxyaristolone (8), (1S,2S,11S)-1,2,12-trihydroxy-aristolone (9). In addition, a seco-cucurbitane triterpene, i.e. 3,4-secocucurbita-4,24E-diene-3-hydroxy-26- carboxylic acid (14) was isolated from both species. The configuration at C-2 of the already known rulepidol (2-hydroxyaristolone, 5) was corrected as S instead of R. Several more aristolane and nardosinane sesquiterpenes, as well as cucurbitane triterpenes, already reported both from European and Chinese samples of R. lepida, were also isolated. Compound 14 showed moderate cell growth inhibitory activity. © 2012 Elsevier Ltd. All rights reserved. Source

Bartoli B.,University of Naples Federico II | Bartoli B.,Complesso Universitario Of Monte Santangelo | Bernardini P.,University of Salento | Bernardini P.,National Institute of Nuclear Physics, Italy | And 95 more authors.
Astrophysical Journal | Year: 2015

The ARGO-YBJ air shower detector monitored the Crab Nebula gamma-ray emission from 2007 November to 2013 February. The integrated signal, consisting of 3.3 × 105 events, reached the statistical significance of 21.1 standard deviations. The obtained energy spectrum in the energy range 0.3-20 TeV can be described by a power law function dN/dE = I 0 (E/2 TeV)-α, with a flux normalization I 0 = (5.2 ± 0.2) × 10-12 photons cm-2 s-1 TeV-1 and α = 2.63 ± 0.05, corresponding to an integrated flux above 1 TeV of 1.97 × 10-11 photons cm-2 s-1. The systematic error is estimated to be less than 30% for the flux normalization and 0.06 for the spectral index. Assuming a power law spectrum with an exponential cutoff dN/dE = I 0 (E/2 TeV)-α exp (-E/E cut), the lower limit of the cutoff energy E cut is 12 TeV, at 90% confidence level. Our extended data set allows the study of the TeV emission over long timescales. Over five years, the light curve of the Crab Nebula in 200-day bins is compatible with a steady emission with a probability of 7.3 × 10-2. A correlated analysis with Fermi-LAT data over 4.5 yr using the light curves of the two experiments gives a Pearson correlation coefficient r = 0.56 ± 0.22. Concerning flux variations on timescales of days, a "blind" search for flares with a duration of 1-15 days gives no excess with a significance higher than four standard deviations. The average rate measured by ARGO-YBJ during the three most powerful flares detected by Fermi-LAT is 205 ± 91 photons day-1, consistent with the average value of 137 ± 10 day-1. © 2015. The American Astronomical Society. All rights reserved. Source

Carbone R.,DellUniversity Pavia | Pautrat Y.,University Paris - Sud
Journal of Statistical Physics | Year: 2015

We study open quantum random walks (OQRWs) for which the underlying graph is a lattice, and the generators of the walk are homogeneous in space. Using the results recently obtained in Carbone and Pautrat (Ann Henri Poincaré, 2015), we study the quantum trajectory associated with the OQRW, which is described by a position process and a state process. We obtain a central limit theorem and a large deviation principle for the position process. We study in detail the case of homogeneous OQRWs on the lattice $$\mathbb {Z}^d$$Zd, with internal space $$\mathfrak {h}=\mathbb {C}^2$$h=C2. © 2015, Springer Science+Business Media New York. Source

Bartoli B.,University of Naples Federico II | Bartoli B.,Complesso Universitario Of Monte Santangelo | Bernardini P.,University of Salento | Bernardini P.,National Institute of Nuclear Physics, Italy | And 94 more authors.
Astroparticle Physics | Year: 2015

The ARGO-YBJ experiment has been in stable data taking from November 2007 till February 2013 at the YangBaJing Cosmic Ray Observatory (4300 m a.s.l.). The detector consists of a single layer of Resistive Plate Chambers (RPCs) (6700 m2) operated in streamer mode. The signal pick-up is obtained by means of strips facing one side of the gas volume. The digital readout of the signals, while allows a high space-time resolution in the shower front reconstruction, limits the measurable energy to a few hundred TeV. In order to fully investigate the 1-10 PeV region, an analog readout has been implemented by instrumenting each RPC with two large size electrodes facing the other side of the gas volume. Since December 2009 the RPC charge readout has been in operation on the entire central carpet (∼5800 m2). In this configuration the detector is able to measure the particle density at the core position where it ranges from tens to many thousands of particles per m2. Thus ARGO-YBJ provides a highly detailed image of the charge component at the core of air showers. In this paper we describe the analog readout of RPCs in ARGO-YBJ and discuss both the performance of the system and the physical impact on the EAS measurements. © 2015 Elsevier B.V. All rights reserved. Source

Middleton D.G.,University of Tubingen | Annand J.R.M.,University of Glasgow | Barbieri C.,RIKEN | Giusti C.,DellUniversity Pavia | And 9 more authors.
European Physical Journal A | Year: 2010

After recent improvements to the Pavia model of two-nucleon knockout from 16O with electromagnetic probes the calculated cross-sections are compared to experimental data from such reactions. Comparison with data from a measurement of the 16O (e,e' pn) reaction cross-section shows much better agreement between the experimental data and the results of the theoretical model than was previously observed. In a comparison with recent data from a measurement of the 16O (γ,pn) reaction cross-section the model over-predicts the measured cross-section at low missing momentum. © 2009 SIF, Springer-Verlag Berlin Heidelberg. Source

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