Showing papers by "Roma Tre University published in 2010"
TL;DR: In this article, the authors present the results of the 9μ m and 18μ m AKARI all-sky survey and detail the operation and data processing leading to the point source detection and measurements.
Abstract: Context. AKARI is the first Japanese astronomical satellite dedicated to infrared astronomy. One of the main purposes of AKARI is the all-sky survey performed with six infrared bands between 9 μ m and 200 μ m during the period from 2006 May 6 to 2007 August 28. In this paper, we present the mid-infrared part (9 μ m and 18 μ m bands) of the survey carried out with one of the on-board instruments, the infrared camera (IRC).Aims. We present unprecedented observational results of the 9 μ m and 18 μ m AKARI all-sky survey and detail the operation and data processing leading to the point source detection and measurements.Methods. The raw data are processed to produce small images for every scan, and the point sources candidates are derived above the 5σ noise level per single scan. The celestial coordinates and fluxes of the events are determined statistically and the reliability of their detections is secured through multiple detections of the same source within milli-seconds, hours, and months from each other.Results. The sky coverage is more than 90% for both bands. A total of 877 091 sources (851 189 for 9 μ m, 195 893 for 18 μ m) are confirmed and included in the current release of the point source catalog. The detection limit for point sources is 50 mJy and 90 mJy for the 9 μ m and 18 μ m bands, respectively. The position accuracy is estimated to be better than 2'' . Uncertainties in the in-flight absolute flux calibration are estimated to be 3% for the 9 μ m band and 4% for the 18 μ m band. The coordinates and fluxes of detected sources in this survey are also compared with those of the IRAS survey and are found to be statistically consistent.
656 citations
TL;DR: In this article, the authors used the ATLAS detector to detect dijet asymmetry in the collisions of lead ions at the Large Hadron Collider and found that the transverse energies of dijets in opposite hemispheres become systematically more unbalanced with increasing event centrality, leading to a large number of events which contain highly asymmetric di jets.
Abstract: By using the ATLAS detector, observations have been made of a centrality-dependent dijet asymmetry in the collisions of lead ions at the Large Hadron Collider. In a sample of lead-lead events with a per-nucleon center of mass energy of 2.76 TeV, selected with a minimum bias trigger, jets are reconstructed in fine-grained, longitudinally segmented electromagnetic and hadronic calorimeters. The transverse energies of dijets in opposite hemispheres are observed to become systematically more unbalanced with increasing event centrality leading to a large number of events which contain highly asymmetric dijets. This is the first observation of an enhancement of events with such large dijet asymmetries, not observed in proton-proton collisions, which may point to an interpretation in terms of strong jet energy loss in a hot, dense medium.
630 citations
TL;DR: In this article, the causal relationship between economy and energy was analyzed by adopting a vector error correction model for non-stationary and cointegrated panel data with a large sample of developed and developing countries and four distinct energy sectors.
339 citations
University of Glasgow1, University of Salerno2, Max Planck Society3, University of Southampton4, University of Paris-Sud5, VU University Amsterdam6, University of Nice Sophia Antipolis7, Washington State University8, University of Zielona Góra9, University of Birmingham10, Cardiff University11, University of Rome Tor Vergata12, Moscow State University13, California Institute of Technology14, fondazione bruno kessler15, Centre national de la recherche scientifique16, University of Cambridge17, University of Tübingen18, University of Urbino19, University of Vienna20, University of Minnesota21, University of Jena22, Northwestern University23, University of Savoy24, Pennsylvania State University25, University of Pisa26, Sapienza University of Rome27, Roma Tre University28, University of Florence29
TL;DR: The status of the project Einstein Telescope (ET), a design study of a third-generation gravitational wave observatory, is reported in this paper, where an overview of the possible science reaches and the technological progress needed to realize a third generation observatory are discussed.
Abstract: Large gravitational wave interferometric detectors, like Virgo and LIGO, demonstrated the capability to reach their design sensitivity, but to transform these machines into an effective observational instrument for gravitational wave astronomy a large improvement in sensitivity is required. Advanced detectors in the near future and third-generation observatories in more than one decade will open the possibility to perform gravitational wave astronomical observations from the Earth. An overview of the possible science reaches and the technological progress needed to realize a third-generation observatory are discussed in this paper. The status of the project Einstein Telescope (ET), a design study of a third-generation gravitational wave observatory, will be reported.
319 citations
TL;DR: A number of algorithmic improvements implemented in the real-time traffic management system ROMA (Railway traffic Optimization by Means of Alternative graphs), achieved by incorporating effective rescheduling algorithms and local rerouting strategies in a tabu search scheme are described.
Abstract: This paper addresses the problem of train conflict detection and resolution, which is dealt every day by traffic controllers to adapt the timetable to delays and other unpredictable events occurring in real-time. We describe a number of algorithmic improvements implemented in the real-time traffic management system ROMA (Railway traffic Optimization by Means of Alternative graphs), achieved by incorporating effective rescheduling algorithms and local rerouting strategies in a tabu search scheme. We alternate a fast heuristic and a truncated branch and bound algorithm for computing train schedules within a short computation time, and investigate the effectiveness of using different neighborhood structures for train rerouting. The computational experiments are based on practical size instances from a dispatching area of the Dutch railway network and include complex disturbances with multiple late trains and blocked tracks. Several small instances are solved to optimality in order to compare the heuristic solutions with the optimum. For small instances, the new tabu search algorithms find optimal solutions. For large instances, the solutions generated by the new algorithms after 20 s of computation are up to more than 15% better than those achieved within 180 s by the previous version of ROMA.
302 citations
University of Valencia1, University of Vienna2, Autonomous University of Barcelona3, Roma Tre University4, University of Silesia in Katowice5, CERN6, Budker Institute of Nuclear Physics7, University of Bari8, SLAC National Accelerator Laboratory9, Goethe University Frankfurt10, Sofia University11, Uppsala University12, Sapienza University of Rome13, Kharkov Institute of Physics and Technology14, Humboldt University of Berlin15, Karlsruhe Institute of Technology16, National Autonomous University of Mexico17, King's College London18, University of Barcelona19, University of Calabria20, Jagiellonian University21, University of Mainz22, University of Bern23, Durham University24, University of Granada25, Princeton University26, Stanford University27
TL;DR: In this paper, the authors discuss the recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled-kaon states, the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta' mesons, and contribution to understand the nature of light scalar mesons.
Abstract: Investigation at a f-factory can shed light on several debated issues in particle physics. We discuss: (i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, (ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled-kaon states, (iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta' mesons, (iv) the contribution to understand the nature of light scalar mesons, and (v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the e(+)e(-) physics in the continuum with the measurements of (multi) hadronic cross sections and the study of gamma gamma processes.
257 citations
Paul Scherrer Institute1, Joint Institute for Nuclear Research2, University of Pavia3, CERN4, Joseph Fourier University5, University of Southampton6, Budker Institute of Nuclear Physics7, Novosibirsk State University8, RWTH Aachen University9, University of Silesia in Katowice10, University of Mainz11, Polish Academy of Sciences12, Humboldt University of Berlin13, École Polytechnique14, Karlsruhe Institute of Technology15, Kharkov Institute of Physics and Technology16, Roma Tre University17, KEK18, University of Alberta19, Jagiellonian University20, University of Bologna21, Spanish National Research Council22, University of Paris23, University of Hawaii24, University of Liverpool25, University of Parma26, University of Freiburg27, Chinese Academy of Sciences28, Baylor University29, University of Wuppertal30
TL;DR: In this paper, the authors present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low energy e+e- colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and sketch the prospects in these fields for the years to come.
Abstract: We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low energy e+e- colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and on tau decays. We sketch the prospects in these fields for the years to come. We emphasise the status and the precision of the Monte Carlo generators used to analyse the hadronic cross section measurements obtained as well with energy scans as with radiative return, to determine luminosities and tau decays. The radiative corrections fully or approximately implemented in the various codes and the contribution of the vacuum polarisation are discussed.
241 citations
TL;DR: In this article, a unified ab initio study of electronic and optical properties of TiO rutile and anatase phases with a combination of density-functional theory and many-body perturbation-theory techniques is presented.
Abstract: We present a unified ab initio study of electronic and optical properties of ${\text{TiO}}_{2}$ rutile and anatase phases with a combination of density-functional theory and many-body perturbation-theory techniques. The consistent treatment of exchange and correlation, with the inclusion of many-body one-particle and two-particles effects in self-energy and electron-hole interaction, produces a high-quality description of electronic and optical properties, giving, for some quantities, the first available estimation for this compound. In particular, we give a quantitative estimate of the electronic and direct optical gaps, clarifying their role with respect to previous measurements obtained by various experimental techniques. We obtain a description for both electronic gap and optical spectra that is consistent with experiments by analyzing the role of different contributions to the experimental optical gap and relating them to the level of theory used in our calculations. We also show the spatial properties of excitons in the two crystalline phases, highlighting the localization character of different optical transitions. This paper aims at understanding and firmly establishing electro-optical bulk properties, yet to be clarified, of this material of fundamental and technological interest for green energy applications.
230 citations
TL;DR: In this article, the authors collected and reanalyzed all available punctual observations of vertical ground displacement taken in the period 1905-2009 with special attention to the period before 1969, to reconstruct in greater detail the deformation history of the Campi Flegrei caldera.
227 citations
TL;DR: In this article, the authors argue that the three-dimensional return flow and slab fragmentation associated with complex oceanic subduction trajectories within the upper mantle can generate focused upwellings and that these may play a significant role in regional tectonics.
213 citations
TL;DR: In this article, the authors used a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent λ_(eff) = 24, 15, 12, and 8 μm monochromatic and bolometric IR luminosity functions (LF) over the full 0 < z < 2.5 redshift range.
Abstract: Context. Studies of the infrared (IR) emission of cosmic sources have proven essential to constraining the evolutionary history of cosmic star formation and the gravitational accretion of nuclear black holes, because many of these events occur inside heavily dust-extinguished environments.
Aims. The Spitzer Space Telescope has provided a large amount of data to constrain the nature and cosmological evolution of infrared source populations. In the present paper we exploit a large homogeneous dataset to derive a self-consistent picture of IR emission based on the time-dependent λ_(eff) = 24, 15, 12, and 8 μm monochromatic and bolometric IR luminosity functions (LF) over the full 0 < z < 2.5 redshift range.
Methods. Our present analysis is based on a combination of data from deep Spitzer surveys of the VIMOS VLT Deep Survey (VVDS-SWIRE) and GOODS fields. To our limiting flux of S_(24) = 400 μJy, our sample derived from VVDS-SWIRE includes 1494 sources, and 666 and 904 sources brighter than S_(24) = 80 μJy are catalogued in GOODS-S and GOODS-N, respectively, for a total area of ~0.9 square degrees. Apart from a few galaxies, we obtain reliable optical identifications and redshifts for all these sources, providing a rich and robust dataset for our luminosity function determination. The final combined reliable sample includes 3029 sources, the fraction with photometric redshifts being 72% over all redshifts and almost all galaxies at z > 1.5. Based on the multiwavelength information available in these areas, we constrain the LFs at 8, 12, 15, and 24 μm. We also infer the total IR luminosities from our best-fit model of the observed SEDs of each source, and use this to derive the bolometric (8–1000 μm) LF and comoving volume emissivity to z ~ 2.5.
Results. In the redshift interval 0 1. The mean redshift of the peak in the source number density shifts with luminosity: the brightest IR galaxies appear to form stars at earlier cosmic times (z > 1.5), while star formation in the less luminous galaxies continues until more recent epochs (z ~ 1 for L_(IR) < 10^(11)_☉), in overall agreement with similar analyses in the literature.
Conclusions. Our results are indicative of a rapid increase in the galaxy IR comoving volume emissivity up to z ~ 1 and a constant average emissivity at z > 1. We also appear to measure a difference in the evolutionary rate of the source number densities as a function of luminosity, which is consistent with the downsizing evolutionary patterns reported for other samples of cosmic sources.
TL;DR: An overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data and the determination of the global energy scale was performed with an uncertainty of 4%.
Abstract: The Tile hadronic calorimeter of the ATLAS detector has undergone extensive testing in the experimental hall since its installation in late 2005. The readout, control and calibration systems have been fully operational since 2007 and the detector has successfully collected data from the LHC single beams in 2008 and first collisions in 2009. This paper gives an overview of the Tile Calorimeter performance as measured using random triggers, calibration data, data from cosmic ray muons and single beam data. The detector operation status, noise characteristics and performance of the calibration systems are presented, as well as the validation of the timing and energy calibration carried out with minimum ionising cosmic ray muons data. The calibration systems’ precision is well below the design value of 1%. The determination of the global energy scale was performed with an uncertainty of 4%.
TL;DR: In this paper, the vibrational properties of carbon nanotube-reinforced composites were studied by employing an equivalent continuum model based on the Eshelby-Mori-Tanaka approach.
University of Glasgow1, University of Salerno2, Max Planck Society3, University of Southampton4, University of Paris-Sud5, University of Nice Sophia Antipolis6, Washington State University7, Istituto Nazionale di Fisica Nucleare8, University of Warsaw9, University of Naples Federico II10, University of Birmingham11, Cardiff University12, University of Rome Tor Vergata13, Moscow State University14, California Institute of Technology15, VU University Amsterdam16, fondazione bruno kessler17, Leibniz University of Hanover18, University of Cambridge19, University of Tübingen20, University of Urbino21, University of Jena22, University of the Balearic Islands23, Northwestern University24, University of Minnesota25, University of Savoy26, Pennsylvania State University27, University of Pisa28, Roma Tre University29, Sapienza University of Rome30, University of Mississippi31
TL;DR: In this article, a special focus is set on evaluating the frequency band below 10Hz where a complex mixture of seismic, gravity gradient, suspension thermal and radiation pressure noise dominates, including the most relevant fundamental noise contributions.
Abstract: Advanced gravitational wave detectors, currently under construction, are expected to directly observe gravitational wave signals of astrophysical origin. The Einstein Telescope, a third-generation gravitational wave detector, has been proposed in order to fully open up the emerging field of gravitational wave astronomy. In this article we describe sensitivity models for the Einstein Telescope and investigate potential limits imposed by fundamental noise sources. A special focus is set on evaluating the frequency band below 10Hz where a complex mixture of seismic, gravity gradient, suspension thermal and radiation pressure noise dominates. We develop the most accurate sensitivity model, referred to as ET-D, for a third-generation detector so far, including the most relevant fundamental noise contributions.
TL;DR: In this article, the authors compare channel steepness index values and 10 Be catchment-averaged erosion rates to well-constrained rock uplift rates in two landscapes in Italy.
Abstract: Rock uplift rates can be difficult to measure over 10 3 –10 5 yr time scales. If, however, a landscape approaches steady state, where hillslope erosion and rock uplift rates are steady and locally similar, then it should be possible to quantify rock uplift rates from hillslope erosion rates. Here, we test this prediction by comparing channel steepness index values and 10 Be catchment-averaged erosion rates to well-constrained rock uplift rates in two landscapes in Italy. The first field area is the Romagna Apennines, northern Italy, where rock uplift rates are relatively uniform, between 0.2 and 0.5 mm/yr (regional mean 0.40 ± 0.15 [SE] mm/yr), and have been steady since 0.9 Ma. The second area is the region around northeastern Sicily and the southernmost Italian peninsula, where rock uplift rates are higher and exhibit a strong spatial gradient, from ∼0.7 to ∼1.6 mm/yr (regional mean 1.09 ± 0.13 [SE] mm/yr). In both regions, channel steepness indices and 10 Be erosion rates vary directly with rock uplift rates. Although there is considerable variability in erosion rates, regionally averaged rates in both the northern (0.46 ± 0.04 [SE] mm/yr) and southern (1.21 ± 0.24 [SE] mm/yr) areas accurately measure rock uplift rates. Although channel steepness indices do not quantify rock uplift rates, they are useful for (1) identifying regional patterns of rock uplift, (2) identifying areas where uplift rates might be expected to be uniform, and (3) informing 10 Be sampling strategies. This study demonstrates that, together, channel steepness and hillslope erosion rates can provide a powerful tool for determining rock uplift rates.
TL;DR: In this article, the authors discuss the relationship between Andean shortening, plate velocities at the trench, and slab geometry beneath South America and argue that the existence of horizontal slab segments, below the Central Andes during Eocene-Oligocene times, and below Peru and North-Central Chile since Pliocene, resulted in the shortening of the continental plate interiors at a large distance from the trench and in stronger interplate coupling and ultimately, in a decrease of the trenchward velocity of the oceanic plate.
TL;DR: The ATLAS Inner Detector as mentioned in this paper is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field, which was completed in 2008 and the detector took part in data-taking with single LHC beams and cosmic rays.
Abstract: The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7.6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22.1 +/- 0.9 mu m and a relative momentum resolution sigma (p) /p=(4.83 +/- 0.16)x10(-4) GeV(-1)xp (T) have been measured for high momentum tracks.
TL;DR: In this article, the density of the Indian plate is estimated after its upper crust is scraped off at the Himalayan front, and it is shown that the continental plate is readily subductable, potentially explaining why the convergence did not halt on collision.
Abstract: The most spectacular example of plate convergence on Earth was the motion of the Indian plate towards Eurasia, and the subsequent collision. Density estimates of the Greater Indian continent, after its upper crust is scraped off at the Himalayan front, suggest that this continental plate is readily subductable, potentially explaining why the convergence did not halt on collision. The most spectacular example of a plate convergence event on Earth is the motion of the Indian plate towards Eurasia at speeds in excess of 18 cm yr−1 (ref. 1), and the subsequent collision. Continental buoyancy usually stalls subduction shortly after collision, as is seen in most sections of the Alpine–Himalayan chain. However, in the Indian section of this chain, plate velocities were merely reduced by a factor of about three when the Indian continental margin impinged on the Eurasian trench about 50 million years ago. Plate convergence, accompanied by Eurasian indentation, persisted throughout the Cenozoic era1,2,3, suggesting that the driving forces of convergence did not vanish on continental collision. Here we estimate the density of the Greater Indian continent, after its upper crust is scraped off at the Himalayan front, and find that the continental plate is readily subductable. Using numerical models, we show that subduction of such a dense continent reduces convergence by a factor similar to that observed. In addition, an imbalance between ridge push and slab pull can develop and cause trench advance and indentation. We conclude that the subduction of the dense Indian continental slab provides a significant driving force for the current India–Asia convergence and explains the documented evolution of plate velocities following continental collision.
TL;DR: In this article, the self energies and tadpoles of the neutral Higgs bosons of the NMSSM were calculated and the two-loop O( α t α s + α b α s ) corrections to the Higgs masses were computed.
TL;DR: In this article, the impact of reciprocal trade agreements (RTAs) on trade flows between partners is investigated using a meta-analysis approach and the authors provide pooled estimates, obtained from fixed and random effects models of the RTAs' effect size on bilateral trade.
Abstract: The gravity model is a workhorse tool applicable in a wide range of empirical fields. It is regularly used to estimate the impact of reciprocal trade agreements (RTAs) on trade flows between partners. The studies report very different estimates since there is a significant difference in datasets, sample sizes, and independent variables. This paper combines, explains, and summarizes a large number of results using a meta-analysis approach. We provide pooled estimates, obtained from fixed and random effects models of the RTAs’ effect size on bilateral trade: the hypothesis that there is no effect of RTAs on trade is robustly rejected at standard significance levels. The information collected on each estimate allows us to test the sensitivity of the results to alternative specifications and differences in the control variables considered, as well as the impact of the publication selection process.
TL;DR: This update will deal with recent reports on the involvement of CuAOs and PAOs in abiotic (salt) stress, wound-healing and host-pathogen interactions.
Carleton University1, Imperial College London2, Fermilab3, RWTH Aachen University4, Queen Mary University of London5, Max Planck Society6, CERN7, Budker Institute of Nuclear Physics8, Karlsruhe Institute of Technology9, Technische Universität München10, Sapienza University of Rome11, Los Alamos National Laboratory12, Stanford University13, University of Minnesota14, University of Glasgow15, Charles University in Prague16, University of Pisa17, Austrian Academy of Sciences18, University of Bergen19, University of Southampton20, Nara Women's University21, University of Florida22, University of Turin23, University of Edinburgh24, University of Warwick25, University of Massachusetts Amherst26, University of Bern27, University of Mainz28, Wayne State University29, Brookhaven National Laboratory30, Folkwang University of the Arts31, University of Victoria32, Washington University in St. Louis33, Indian Institute of Technology Madras34, University of Melbourne35, Princeton University36, Roma Tre University37, York University38, University of California, Irvine39, University of Valencia40, University of Padua41, University of Barcelona42, Tata Institute of Fundamental Research43, University of Vienna44, University of Paris-Sud45, University of Kentucky46, University of Oxford47, Iowa State University48, University of Bristol49, Rutherford Appleton Laboratory50, University of Texas at Austin51, École Polytechnique Fédérale de Lausanne52, University of California, Santa Cruz53, University of Cincinnati54, Purdue University55, ETH Zurich56, Queen's University57, Indiana University58, University of Cambridge59, University of Ljubljana60
TL;DR: In this time frame, measurements and the theoretical interpretation of their results have advanced tremendously as mentioned in this paper and a much broader understanding of flavor particles has been achieved, apart from their masses and quantum numbers, there now exist detailed measurements of the characteristics of their interactions allowing stringent tests of Standard Model predictions.
TL;DR: The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented in this paper, where the charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transversal momentum and charge multiplicity are measured for events with at least one charged particle in the kinematic range.
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20 Apr 2010TL;DR: In this paper, a mathematical model describing electrostatic actuated MEMS is presented, which can be used as a motivational introduction to many recent methods of nonlinear analysis and PDEs through the analysis of a set of equations that have enormous practical significance.
Abstract: Micro- and nanoelectromechanical systems (MEMS and NEMS), which combine electronics with miniature-size mechanical devices, are essential components of modern technology It is the mathematical model describing 'electrostatically actuated' MEMS that is addressed in this monograph Even the simplified models that the authors deal with still lead to very interesting second- and fourth-order nonlinear elliptic equations (in the stationary case) and to nonlinear parabolic equations (in the dynamic case) While nonlinear eigenvalue problems - where the stationary MEMS models fit - are a well-developed field of PDEs, the type of inverse square nonlinearity that appears here helps shed a new light on the class of singular supercritical problems and their specific challenges Besides the practical considerations, the model is a rich source of interesting mathematical phenomena Numerics, formal asymptotic analysis, and ODE methods give lots of information and point to many conjectures However, even in the simplest idealized versions of electrostatic MEMS, one essentially needs the full available arsenal of modern PDE techniques to do the required rigorous mathematical analysis, which is the main objective of this volume This monograph could therefore be used as an advanced graduate text for a motivational introduction to many recent methods of nonlinear analysis and PDEs through the analysis of a set of equations that have enormous practical significance
TL;DR: Nonquantum entanglement or inseparability between the polarization and spatial degrees of freedom of an electromagnetic beam whose polarization is not homogeneous is shown to provide the physical basis to resolve this issue in a definitive manner.
Abstract: The issue raised in this Letter is classical, not only in the sense of being nonquantum, but also in the sense of being quite ancient: which subset of 4 X 4 real matrices should be accepted as physical Mueller matrices in polarization optics? Nonquantum entanglement or inseparability between the polarization and spatial degrees of freedom of an electromagnetic beam whose polarization is not homogeneous is shown to provide the physical basis to resolve this issue in a definitive manner.
TL;DR: In this article, the importance of researchers' individual characteristics and their institutional environments in explaining the propensity to engage in different types of U-I linkages has been examined and found to be important factors.
TL;DR: In this paper, molecular dynamics simulations of deeply supercooled SPC/E water confined in a cylindrical pore of MCM-41 silica material are presented.
Abstract: We present here molecular dynamics simulations of deeply supercooled SPC/E water confined in a cylindrical pore of MCM-41 silica material. By a layer analysis of the tag particle density correlators, we are able to extract the α-relaxation time of the mobile portion of the confined water. This relaxation time is the same as what can be extracted from neutron scattering experiments. From examination of the temperature-dependent behavior of the relaxation time and the dynamic susceptibility, we locate a dynamic crossover at T = (215 ± 5) K and a corresponding peak in the specific heat, in agreement with experimental findings in confined water and simulations of the bulk water. Our study demonstrates that the recent results of the experiments on confined water are extremely relevant for the comprehension of low-temperature bulk properties of water.
TL;DR: Experiments performed on FTU (Frascati Tokamak Upgrade) show that the coupled radio frequency power can penetrate into high-density plasmas due to weaker plasma edge effects, thus extending the effective range of lower hybrid current drive towards the domain relevant for fusion reactors.
Abstract: Future tokamak nuclear fusion reactors depend on efficient current drive methods, but it is hard to penetrate the high-density plasma in these devices. In this paper the authors show that radio frequency waves coupled to lower hybrid plasma waves, when the peripheral temperature of the plasma is high, can penetrate the plasma core.
TL;DR: A search for new heavy particles manifested as resonances in two-jet final states in 7 TeV proton-proton collisions by the LHC is presented, extending the reach of previous experiments.
Abstract: A search for new heavy particles manifested as resonances in two-jet final states is presented. The data were produced in 7 TeV proton-proton collisions by the LHC and correspond to an integrated luminosity of 315 nb(-1) collected by the ATLAS detector. No resonances were observed. Upper limits were set on the product of cross section and signal acceptance for excited-quark (q*) production as a function of q* mass. These exclude at the 95% C. L. the q* mass interval 0: 30< m(q)*< 1:26 TeV, extending the reach of previous experiments.
TL;DR: In this paper, an almost complete, flux-limited subsample of 31 sources has been defined by selecting the FERO sources observed by the RXTE all-sky Slew Survey with a count rate in the 3-8 keV energy band greater than 1 cts/sec.
Abstract: Context. Accretion models predict that fluorescence lines broadened by relativistic effects should arise from reflection of X-ray emission onto the inner region of the accretion disc surrounding the central black hole of active galactic nuclei (AGN). The theory behind the origin of relativistic lines is well established, and observational evidence from a moderate number of sources seems to support the existence of these lines. Aims. The aim of this work is to establish the fraction of AGN with relativistic Fe Kα lines, and study possible correlations with source physical properties. Methods. An XMM-Newton collection of 149 radio-quiet Type 1 AGN has been systematically and uniformly analysed in order to search for evidence of a relativistically broadened Fe Kα line. To enable statistical studies, an almost complete, flux-limited subsample of 31 sources has been defined by selecting the FERO sources observed by the RXTE all-sky Slew Survey with a count rate in the 3– 8 keV energy band greater than 1 cts/sec. The 2–10 keV spectra of the FERO sources where compared with a complex model including most of the physical components observed in the X-ray spectra of Seyfert galaxies: a power law primary continuum modified by nonrelativistic Compton reflection and warm absorption, plus a series of narrow Fe line reflection features. Results. The observed fraction of sources in the flux-limited sample that show strong evidence of a relativistic Fe Kα line is 36%. This number can be interpreted as a lower limit to the fraction of sources that present a relativistic broad Fe Kα line in the wider AGN population. The average line equivalent width (EW) is of the order of 100 eV. The outcome of the fit yields an average disc inclination angle of 28 ± 5 ◦ and an average power-law index of the radial disc emissivity law of 2.4 ± 0.4. The spin value is well constrained only in 2 cases (MCG-6-30-15 and MRK 509); in the rest of the cases, whenever a constraint can be placed, it always implies the rejection of the static black hole solution. The Fe Kα line EW does not correlate with disc parameters or with system physical properties, such as black hole mass, accretion rate, and hard X-ray luminosity.