Showing papers by "Roma Tre University published in 2014"

The Systems View of Life: A Unifying Vision

Abstract: Over the past thirty years, a new systemic conception of life has emerged at the forefront of science. New emphasis has been given to complexity, networks, and patterns of organisation, leading to a novel kind of 'systemic' thinking. This volume integrates the ideas, models, and theories underlying the systems view of life into a single coherent framework. Taking a broad sweep through history and across scientific disciplines, the authors examine the appearance of key concepts such as autopoiesis, dissipative structures, social networks, and a systemic understanding of evolution. The implications of the systems view of life for health care, management, and our global ecological and economic crises are also discussed. Written primarily for undergraduates, it is also essential reading for graduate students and researchers interested in understanding the new systemic conception of life and its implications for a broad range of professions - from economics and politics to medicine, psychology and law.

Acinetobacter baumannii: evolution of a global pathogen.

Abstract: Acinetobacter baumannii is an opportunistic nosocomial pathogen and one of the six most important multidrug-resistant microorganisms in hospitals worldwide. This human pathogen is responsible for a vast array of infections, of which ventilator-associated pneumonia and bloodstream infections are the most common, and mortality rates can reach 35%. Community-acquired infections have also been reported, but few strains have been recovered from environmental sources and infection reservoirs external to the hospital have not been identified. The majority of A. baumannii infections are caused by two main population clones with worldwide distribution. Infection outbreaks are often associated with multidrug resistance, including the recent emergence of strains resistant to all available antibiotics. Nevertheless, A. baumannii virulence traits and pathogenic potential have mostly remained elusive. The recent expansion of A. baumannii sequenced genomes has permitted the development of large-array phylogenomic and phenotypic analyses, which can offer valuable insights into the evolution and adaptation of A. baumannii as a human pathogen. This review summarises these recent advances, with particular focus on A. baumannii evolutionary and genomic aspects, and proposes new avenues of research.

Mantle dynamics in the Mediterranean

Abstract: The Mediterranean offers a unique opportunity to study the driving forces of tectonic deformation within a complex mobile belt. Lithospheric dynamics are affected by slab rollback and collision of two large, slowly moving plates, forcing fragments of continental and oceanic lithosphere to interact. This paper reviews the rich and growing set of constraints from geological reconstructions, geodetic data, and crustal and upper mantle heterogeneity imaged by structural seismology. We proceed to discuss a conceptual and quantitative framework for the causes of surface deformation. Exploring existing and newly developed tectonic and numerical geodynamic models, we illustrate the role of mantle convection on surface geology. A coherent picture emerges which can be outlined by two, almost symmetric, upper mantle convection cells. The downwellings are found in the center of the Mediterranean and are associated with the descent of the Tyrrhenian and the Hellenic slabs. During plate convergence, these slabs migrated backward with respect to the Eurasian upper plate, inducing a return flow of the asthenosphere from the backarc regions towards the subduction zones. This flow can be found at large distance from the subduction zones, and is at present expressed in two upwellings beneath Anatolia and eastern Iberia. This convection system provides an explanation for the general pattern of seismic anisotropy in the Mediterranean, first-order Anatolia and Adria microplate kinematics, and may contribute to the high elevation of scarcely deformed areas such as Anatolia and Eastern Iberia. More generally, the Mediterranean is an illustration of how upper mantle, small-scale convection leads to intraplate deformation and complex plate boundary reconfiguration at the westernmost terminus of the Tethyan collision.

Electron and photon energy calibration with the ATLAS detector using LHC Run 1 data

Abstract: This paper presents the electron and photon energy calibration achieved with the ATLAS detector using about 25 fb(-1) of LHC proton-proton collision data taken at centre-of-mass energies of root s = 7 and 8 TeV. The reconstruction of electron and photon energies is optimised using multivariate algorithms. The response of the calorimeter layers is equalised in data and simulation, and the longitudinal profile of the electromagnetic showers is exploited to estimate the passive material in front of the calorimeter and reoptimise the detector simulation. After all corrections, the Z resonance is used to set the absolute energy scale. For electrons from Z decays, the achieved calibration is typically accurate to 0.05% in most of the detector acceptance, rising to 0.2% in regions with large amounts of passive material. The remaining inaccuracy is less than 0.2-1% for electrons with a transverse energy of 10 GeV, and is on average 0.3% for photons. The detector resolution is determined with a relative inaccuracy of less than 10% for electrons and photons up to 60 GeV transverse energy, rising to 40% for transverse energies above 500 GeV.

Measurement of the Z/γ* boson transverse momentum distribution in pp collisions at √s = 7 TeV with the ATLAS detector

Abstract: This paper describes a measurement of the Z/gamma* boson transverse momentum spectrum using ATLAS proton-proton collision data at a centre-of-mass energy of root s = 7TeV at the LHC. The measurement is performed in the Z/gamma* -> e(+)e(-) and Z/gamma* -> mu(+)mu(-) channels, using data corresponding to an integrated luminosity of 4.7 fb(-1). Normalized differential cross sections as a function of the Z/gamma* boson transverse momentum are measured for transverse momenta up to 800 GeV. The measurement is performed inclusively for Z/gamma* rapidities up to 2.4, as well as in three rapidity bins. The channel results are combined, compared to perturbative and resummed QCD calculations and used to constrain the parton shower parameters of Monte Carlo generators.

Search for squarks and gluinos with the ATLAS detector in final states with jets and missing transverse momentum using √s = 8 TeV proton-proton collision data

Abstract: A search for squarks and gluinos in final states containing high-p T jets, missing transverse momentum and no electrons or muons is presented. The data were recorded in 2012 by the ATLAS experiment in s√=8 TeV proton-proton collisions at the Large Hadron Collider, with a total integrated luminosity of 20.3 fb−1. Results are interpreted in a variety of simplified and specific supersymmetry-breaking models assuming that R-parity is conserved and that the lightest neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 1330 GeV for a simplified model incorporating only a gluino and the lightest neutralino. For a simplified model involving the strong production of first- and second-generation squarks, squark masses below 850 GeV (440 GeV) are excluded for a massless lightest neutralino, assuming mass degenerate (single light-flavour) squarks. In mSUGRA/CMSSM models with tan β = 30, A 0 = −2m 0 and μ > 0, squarks and gluinos of equal mass are excluded for masses below 1700 GeV. Additional limits are set for non-universal Higgs mass models with gaugino mediation and for simplified models involving the pair production of gluinos, each decaying to a top squark and a top quark, with the top squark decaying to a charm quark and a neutralino. These limits extend the region of supersymmetric parameter space excluded by previous searches with the ATLAS detector.

Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data

Abstract: This paper presents the performance of the ATLAS muon reconstruction during the LHC run with pp collisions at root s = 7-8 TeV in 2011-2012, focusing mainly on data collected in 2012. Measurements ...

The VIMOS Public Extragalactic Redshift Survey (VIPERS) - an unprecedented view of galaxies and large-scale structure at 0.5 < z < 1.2

Abstract: We describe the construction and general features of VIPERS, the VIMOS Public Extragalactic Redshift Survey. This `Large Programme' has been using the ESO VLT with the aim of building a spectroscopic sample of ~100,000 galaxies with i_{AB}<22.5 and 0.5

Electron reconstruction and identification efficiency measurements with the atlas detector using the 2011 lhc proton-proton collision data

Abstract: Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton-proton collision data collected in 2011 at TeV and corresponding to an integrated luminosity of 4.7 fb. Tag-and-probe methods using events with leptonic decays of and bosons and mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.

Measurement of the Higgs Boson Mass from the H → γγ and H → ZZ* → 4ℓ Channels in pp Collisions at Center-of-Mass Energies of 7 and 8 TeV with the ATLAS Detector

Abstract: An improved measurement of the mass of the Higgs boson is derived from a combined fit to the reconstructed invariant mass spectra of the decay channels H -> gamma gamma and H -> ZZ* -> 4l. The analysis uses the pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at center-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of 25 fb(-1). The measured value of the Higgs boson mass is m(H) = 125.36 +/- 0.37(stat) +/- 0.18 (syst) GeV. This result is based on improved energy-scale calibrations for photons, electrons, and muons as well as other analysis improvements, and supersedes the previous result from ATLAS. Upper limits on the total width of the Higgs boson are derived from fits to the invariant mass spectra of the H -> gamma gamma and H -> ZZ* -> 4l decay channels.

A fast and long-lived outflow from the supermassive black hole in NGC 5548

Abstract: Supermassive black holes in the nuclei of active galaxies expel large amounts of matter through powerful winds of ionized gas. The archetypal active galaxy NGC 5548 has been studied for decades, and high-resolution x-ray and ultraviolet (UV) observations have previously shown a persistent ionized outflow. An observing campaign in 2013 with six space observatories shows the nucleus to be obscured by a long-lasting, clumpy stream of ionized gas not seen before. It blocks 90% of the soft x-ray emission and causes simultaneous deep, broad UV absorption troughs. The outflow velocities of this gas are up to five times faster than those in the persistent outflow, and, at a distance of only a few light days from the nucleus, it may likely originate from the accretion disk.

Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton–proton collision data

Abstract: This paper presents the performance of the ATLAS muon reconstruction during the LHC run with pp collisions at root s = 7-8 TeV in 2011-2012, focusing mainly on data collected in 2012. Measurements ...

Microscopic Theory of the Inverse Edelstein Effect

Abstract: We provide a precise microscopic definition of the recently observed inverse Edelstein effect in which a nonequilibrium spin accumulation in the plane of a two-dimensional (interfacial) electron gas drives an electric current perpendicular to its own direction. The drift-diffusion equations that govern the effect are presented and applied to the interpretation of the experiments.

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 8 TeV pp collisions with the ATLAS detector

Abstract: Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in root s=8 TeV pp collisions with the ATLAS detector

Search for dark matter in events with a hadronically decaying W or Z boson and missing transverse momentum in pp collisions at √s = 8 TeV with the ATLAS detector

Abstract: A search is presented for dark matter pair production in association with a W or Z boson in pp collisions representing 20.3 fb(-1) of integrated luminosity at root s = 8 TeV using data recorded with the ATLAS detector at the Large Hadron Collider. Events with a hadronic jet with the jet mass consistent with a W or Z boson, and with large missing transverse momentum are analyzed. The data are consistent with the standard model expectations. Limits are set on the mass scale in effective field theories that describe the interaction of dark matter and standard model particles, and on the cross section of Higgs production and decay to invisible particles. In addition, cross section limits on the anomalous production of W or Z bosons with large missing transverse momentum are set in two fiducial regions.

Search for top squark pair production in final states with one isolated lepton, jets, and missing transverse momentum in √s=8 TeV pp collisions with the ATLAS detector

Abstract: The results of a search for top squark (stop) pair production in final states with one isolated lepton, jets, and missing transverse momentum are reported. The analysis is performed with proton-proton collision data at root s = 8 TeV collected with the ATLAS detector at the LHC in 2012 corresponding to an integrated luminosity of 20 fb(-1). The lightest supersymmetric particle (LSP) is taken to be the lightest neutralino which only interacts weakly and is assumed to be stable. The stop decay modes considered are those to a top quark and the LSP as well as to a bottom quark and the lightest chargino, where the chargino decays to the LSP by emitting a W boson. A wide range of scenarios with different mass splittings between the stop, the lightest neutralino and the lightest chargino are considered, including cases where the W bosons or the top quarks are off-shell. Decay modes involving the heavier charginos and neutralinos are addressed using a set of phenomenological models of supersymmetry. No significant excess over the Standard Model prediction is observed. A stop with a mass between 210 and 640 GeV decaying directly to a top quark and a massless LSP is excluded at 95% confidence level, and in models where the mass of the lightest chargino is twice that of the LSP, stops are excluded at 95% confidence level up to a mass of 500 GeV for an LSP mass in the range of 100 to 150 GeV. Stringent exclusion limits are also derived for all other stop decay modes considered, and model-independent upper limits are set on the visible cross-section for processes beyond the Standard Model.

The VIMOS Public Extragalactic Survey (VIPERS) - First Data Release of 57 204 spectroscopic measurements

Abstract: We present the first Public Data Release (PDR-1) of the VIMOS Public Extragalactic Survey (VIPERS). It comprises 57 204 spectroscopic measurements together with all additional information necessary for optimal scientific exploitation of the data, in particular the associated photometric measurements and quantification of the photometric and survey completeness. VIPERS is an ESO Large Programme designed to build a spectroscopic sample of ' 100 000 galaxies with iAB < 22.5 and 0.5 < z < 1.5 with high sampling rate (~45%). The survey spectroscopic targets are selected from the CFHTLS-Wide five-band catalogues in the W1 and W4 fields. The final survey will cover a total area of nearly 24 deg2, for a total comoving volume between z = 0.5 and 1.2 of ~4x10^7 h^(-3)Mpc^3 and a median galaxy redshift of z~0.8. The release presented in this paper includes data from virtually the entire W4 field and nearly half of the W1 area, thus representing 64% of the final dataset. We provide a detailed description of sample selection, observations and data reduction procedures; we summarise the global properties of the spectroscopic catalogue and explain the associated data products and their use, and provide all the details for accessing the data through the survey database (http://vipers.inaf.it) where all information can be queried interactively.

Mortar-based systems for externally bonded strengthening of masonry

Abstract: Mortar-based composite materials appear particularly promising for use as externally bonded reinforcement (EBR) systems for masonry structures. Nevertheless, their mechanical performance, which may significantly differ from that of Fibre Reinforced Polymers, is still far from being fully investigated. Furthermore, standardized and reliable testing procedures have not been defined yet. The present paper provides an insight on experimental-related issues arising from campaigns on mortar-based EBRs carried out by laboratories in Italy, Portugal and Spain. The performance of three reinforcement systems made out of steel, carbon and basalt textiles embedded in inorganic matrices has been investigated by means of uniaxial tensile coupon testing and bond tests on brick and stone substrates. The experimental results contribute to the existing knowledge regarding the structural behaviour of mortar-based EBRs against tension and shear bond stress, and to the development of reliable test procedures aiming at their homogenization/standardization.

Human Brain Distinctiveness Based on EEG Spectral Coherence Connectivity

Abstract: The use of EEG biometrics, for the purpose of automatic people recognition, has received increasing attention in the recent years. Most of the current analyses rely on the extraction of features characterizing the activity of single brain regions, like power spectrum estimation, thus neglecting possible temporal dependencies between the generated EEG signals. However, important physiological information can be extracted from the way different brain regions are functionally coupled. In this study, we propose a novel approach that fuses spectral coherence-based connectivity between different brain regions as a possibly viable biometric feature. The proposed approach is tested on a large dataset of subjects (N = 108) during eyes-closed (EC) and eyes-open (EO) resting state conditions. The obtained recognition performance shows that using brain connectivity leads to higher distinctiveness with respect to power-spectrum measurements, in both the experimental conditions. Notably, a 100% recognition accuracy is obtained in EC and EO when integrating functional connectivity between regions in the frontal lobe, while a lower 97.5% is obtained in EC (96.26% in EO) when fusing power spectrum information from parieto-occipital (centro-parietal in EO) regions. Taken together, these results suggest that the functional connectivity patterns represent effective features for improving EEG-based biometric systems.

Quantum teleportation on a photonic chip

Abstract: Quantum teleportation is a fundamental concept in quantum physics that now finds important applications at the heart of quantum technology, including quantum relays, quantum repeaters and linear optics quantum computing. Photonic implementations have largely focused on achieving long-distance teleportation for decoherence-free quantum communication. Teleportation also plays a vital role in photonic quantum computing for which large linear optical networks will probably require an integrated architecture. Here, we report a fully integrated implementation of quantum teleportation in which all key parts of the circuit - entangled state preparation, Bell-state analysis and tomographic state measurement - are performed on a reconfigurable photonic chip. We also show that a novel element-wise characterization method is critical to the mitigation of component errors, a key technique that will become increasingly important as integrated circuits reach the higher complexities necessary for quantum enhanced operation.

Search for neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at √s=8 TeV with the ATLAS detector

Abstract: A search for the neutral Higgs bosons predicted by the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is performed on data from proton-proton collisions at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the Large Hadron Collider. The samples used for this search were collected in 2012 and correspond to integrated luminosities in the range 19.5-20.3 fb−1. The MSSM Higgs bosons are searched for in the τ τ final state. No significant excess over the expected background is observed, and exclusion limits are derived for the production cross section times branching fraction of a scalar particle as a function of its mass. The results are also interpreted in the MSSM parameter space for various benchmark scenarios.

Search for direct top-squark pair production in final states with two leptons in pp collisions at √s = 8 TeV with the ATLAS detector

Abstract: A search is presented for direct top-squark pair production in final states with two leptons (electrons or muons) of opposite charge using 203 fb−1 of pp collision data at √s = 8 TeV, collected by the ATLAS experiment at the Large Hadron Collider in 2012 No excess over the Standard Model expectation is found The results are interpreted under the separate assumptions (i) that the top squark decays to a b-quark in addition to an on-shell chargino whose decay occurs via a real or virtual W boson, or (ii) that the top squark decays to a t-quark and the lightest neutralino A top squark with a mass between 150 GeV and 445 GeV decaying to a b-quark and an on-shell chargino is excluded at 95% confidence level for a top squark mass equal to the chargino mass plus 10 GeV, in the case of a 1 GeV lightest neutralino Top squarks with masses between 215 (90) GeV and 530 (170) GeV decaying to an on-shell (off-shell) t-quark and a neutralino are excluded at 95% confidence level for a 1 GeV neutralino

Analysis of country-wide internet outages caused by censorship

Abstract: In the first months of 2011, Internet communications were disrupted in several North African countries in response to civilian protests and threats of civil war In this paper, we analyze episodes of these disruptions in two countries: Egypt and Libya Our analysis relies on multiple sources of large-scale data already available to academic researchers: BGP interdomain routing control plane data, unsolicited data plane traffic to unassigned address space, active macroscopic traceroute measurements, RIR delegation files, and MaxMind's geolocation database We used the latter two data sets to determine which IP address ranges were allocated to entities within each country, and then mapped these IP addresses of interest to BGP-announced address ranges (prefixes) and origin autonomous systems (ASs) using publicly available BGP data repositories in the US and Europe We then analyzed observable activity related to these sets of prefixes and ASs throughout the censorship episodes Using both control plane and data plane data sets in combination allowed us to narrow down which forms of Internet access disruption were implemented in a given region over time Among other insights, we detected what we believe were Libya's attempts to test firewall-based blocking before they executed more aggressive BGP-based disconnection Our methodology could be used, and automated, to detect outages or similar macroscopically disruptive events in other geographic or topological regions

A Smart City Application: A Fully Controlled Street Lighting Isle Based on Raspberry-Pi Card, a ZigBee Sensor Network and WiMAX

Abstract: A smart city application has been realized and tested. It is a fully remote controlled isle of lamp posts based on new technologies. It has been designed and organized in different hierarchical layers, which perform local activities to physically control the lamp posts and transmit information with another for remote control. Locally, each lamp post uses an electronic card for management and a ZigBee tlc network transmits data to a central control unit, which manages the whole isle. The central unit is realized with a Raspberry-Pi control card due to its good computing performance at very low price. Finally, a WiMAX connection was tested and used to remotely control the smart grid, thus overcoming the distance limitations of commercial Wi-Fi networks. The isle has been realized and tested for some months in the field.