ATLAS RPC offline monitoring and data quality assessment

In this work several aspects of ATLAS RPC offline monitoring and data quality assessment are illustrated with cosmics data selected by RPC trigger. These correspond to trigger selection, front-end mapping, detection efficiency and occupancy, which are studied in terms of low level quantities such as: RPC off-line hits and standalone tracks. The tools and techniques presented are also extended to the forthcoming LHC p-p beam collisions.Comment: Poster section at ICHEP08, Philadelphia, USA, July 2008. 3 pages, LaTeX, 3 eps figure

GRB970228 and the class of GRBs with an initial spikelike emission: do they follow the Amati relation?

On the basis of the recent understanding of GRB050315 and GRB060218, we return to GRB970228, the first Gamma-Ray Burst (GRB) with detected afterglow. We proposed it as the prototype for a new class of GRBs with "an occasional softer extended emission lasting tenths of seconds after an initial spikelike emission". Detailed theoretical computation of the GRB970228 light curves in selected energy bands for the prompt emission are presented and compared with observational BeppoSAX data. From our analysis we conclude that GRB970228 and likely the ones of the above mentioned new class of GRBs are "canonical GRBs" have only one peculiarity: they exploded in a galactic environment, possibly the halo, with a very low value of CBM density. Here we investigate how GRB970228 unveils another peculiarity of this class of GRBs: they do not fulfill the "Amati relation". We provide a theoretical explanation within the fireshell model for the apparent absence of such correlation for the GRBs belonging to this new class.Comment: 5 pages, 3 figures, in the Proceedings of the "4th Italian-Sino Workshop on Relativistic Astrophysics", held in Pescara, Italy, July 20-28, 2007, C.L. Bianco, S.-S. Xue, Editor

The Amati relation in the "fireshell" model

(Shortened) CONTEXT: [...] AIMS: Motivated by the relation proposed by Amati and collaborators, we look within the ``fireshell'' model for a relation between the peak energy E_p of the \nu F_\nu total time-integrated spectrum of the afterglow and the total energy of the afterglow E_{aft}, which in our model encompasses and extends the prompt emission. METODS: [...] Within the fireshell model [...] We can then build two sets of ``gedanken'' GRBs varying the total energy of the electron-positron plasma E^{e^\pm}_{tot} and keeping the same baryon loading B of GRB050315. The first set assumes for the effective CBM density the one obtained in the fit of GRB050315. The second set assumes instead a constant CBM density equal to the average value of the GRB050315 prompt phase. RESULTS: For the first set of ``gedanken'' GRBs we find a relation E_p\propto (E_{aft})^a, with a = 0.45 \pm 0.01, whose slope strictly agrees with the Amati one. Such a relation, in the limit B \to 10^{-2}, coincides with the Amati one. Instead, in the second set of ``gedanken'' GRBs no correlation is found. CONCLUSIONS: Our analysis excludes the Proper-GRB (P-GRB) from the prompt emission, extends all the way to the latest afterglow phases and is independent on the assumed cosmological model, since all ``gedanken'' GRBs are at the same redshift. The Amati relation, on the other hand, includes also the P-GRB, focuses on the prompt emission only, and is therefore influenced by the instrumental threshold which fixes the end of the prompt emission, and depends on the assumed cosmology. This may well explain the intrinsic scatter observed in the Amati relation.Comment: 4 pages, 5 figures, to appear on A&A Letter

Scalar-tensor analysis of an exponential Lagrangian for the Gravitational Field

Within the scheme of modified gravity, an exponential Lagrangian density will be considered, and the corresponding scalar-tensor description will be addressed for both positive and negative values of the cosmological constant. For negative values of the cosmological term, the potential of the scalar field exhibits a minimum, around which scalar-field equations can be linearized. The study of the deSitter regime shows that a comparison with the modified-gravity description is possible in an off-shell region, i.e., in a region where the classical equivalence between the two formulations is not fulfilled. Furthermore, despite the negative cosmological constant, an accelerating deSitter phase is predicted in the region where the series expansion of the exponential term does not hold. For positive values of the cosmological constant, the quantum regime is analyzed within the framework of Loop Quantum Cosmology.Comment: 8 pages, 2 figures, to appear in the proceedings of'' 4th Italian-Sino Workshop on Relativistic Astrophysics'', AIP Conference Serie

Secondary metabolites with ecologic and medicinal implications in Anthemis cretica subsp. petraea from Majella National Park

Anthemis cretica subsp. petraea (Ten.) Greuter is a plant belonging to the Asteraceae family and endemic of central Italy. In this paper, the first analysisof the ethanolic fraction of samples collected in the Majella National Park is reported. Seven compounds were isolated and identified namely parthenolide (1), 9α-acetoxyparthenolide (2), tamarixetin (3), 7-hydroxycoumarin (4), 4'-hydroxyacetophenone (5), leucanthemitol (conduritol F) (6),and proto-quercitol (7). Isolation of the compounds was achieved by means ofcolumn chromatography (CC), while their identification was achieved through spectroscopic and spectrometric techniques. The presence of these compounds is of great relevance. Compounds 1 and 2 are chemosystematic markers of the family, thus confirming the correct botanical classification of the species. Conversely, compounds 3, 5,and 7 were identified for the first time in the species and, instead, confirm the tendency of endemic entities to develop characteristic metabolite patterns in respect to cosmopolite species. Moreover, the presence of compounds 6 and 7 has ecologic implications and may be linked to this taxon’s adaption to dry environments. The production of these osmolytes may, in fact, represent the reason why this species is able to survive in extreme conditions of aridity. Lastly, from a medicinal standpoint, the isolated compounds are endowed with interesting biological activities and may justify, on a molecular base, the widespread traditional uses of the Anthemis species, as well as a basis for the use ofthe subspecies petraea

An expression for the water-sediment moving layer in unsteady flows valid for open channels and embankments

Abstract. During the floods, the effects of sediment transport in river beds are particulary significant and can be studied through the evolution of the water-sediment layer which moves in the lower part of a flow, named "moving layer". Moving layer variations along rivers lead to depositions and erosions and are typically unsteady, but are often tackled with expressions developed for steady (equilibrium) conditions. In this paper, we develop an expression for the moving layer in unsteady conditions and calibrate it with experimental data. During laboratory tests, we have in fact reproduced a rapidly changing unsteady flow by the erosion of a granular steep slope. Results have shown a clear tendency of the moving layer, for fixed discharges, toward equilibrium conditions. Knowing the equilibrium achievement has presented many difficulties, being influenced by the choice of the equilibrium expression and moreover by the estimation of the parameters involved (for example friction angle). Since we used only data relevant to hyper-concentrated mono-dimensional flows for the calibration – occurring for slope gradients in the range 0.03–0.20 – our model can be applied both on open channels and on embankments/dams, providing that the flows can be modelled as mono-dimensional, and that slopes and applied shear stress levels fall within the considered ranges

Optical Interconnection Networks Based on Microring Resonators

Abstract — Interconnection networks must transport an always increasing information density and connect a rising number of processing units. Electronic technologies have been able to sustain the traffic growth rate, but are getting close to their physical limits. In this context, optical interconnection networks are becoming progressively more attractive, especially because new photonic devices can be directly integrated in CMOS technology. Indeed, interest in microring resonators as switching components is rising, but their usability in full optical interconnection architectures is still limited by their physical characteristics. Indeed, differently from classical devices used for switching, switching elements based on microring resonators exhibit asymmetric power losses depending on the output ports input signals are directed to. In this paper, we study classical interconnection architectures such as crossbar, Benes and Clos networks exploiting microring resonators as building blocks. Since classical interconnection networks lack either scalability or complexity, we propose two new architectures to improve performance of microring based interconnection networks while keeping a reasonable complexity. I

GRBs and the thermalization process of electron-positron plasmas

We discuss the temporal evolution of the pair plasma created in Gamma-Ray Burst sources. A particular attention is paid to the relaxation of the plasma into thermal equilibrium. We also discuss the connection between the dynamics of expansion and the spatial geometry of the plasma. The role of the baryonic loading parameter is emphasized.Comment: 4 pages, 3 figures, in the Proceedings of the "Gamma Ray Bursts 2007" meeting, November 5-9, 2007, Santa Fe, New Mexico, US

Optical Interconnection Architectures based on Microring Resonators

Abstract: Microring resonators are an interesting device to build integrated optical interconnects, but their asymmetric loss behavior could limit the scalability of classical optical interconnects. We present new interconnects able to increase scalability with limited complexity