Scale invariant scalar metric fluctuations during inflation: non-perturbative formalism from a 5D vacuum

We extend to 5D an approach of a 4D non-perturbative formalism to study scalar metric fluctuations of a 5D Riemann-flat de Sitter background metric. In contrast with the results obtained in 4D, the spectrum of cosmological scalar metric fluctuations during inflation can be scale invariant and the background inflaton field can take sub-Planckian values.Comment: final version to be published in Eur. Phys. J.

Porosity Reduction in the High-Speed Processing of Glass-Fiber Composites by Resin Transfer Molding (RTM)

High-speed processing is essential to achieve lower production cost in the fabrication of fiber-reinforced composites with the current liquid molding practices. A major consequence of increasing the resin injection velocity is the formation of defects such as voids and dry regions that decrease the load-bearing capability of the composite. Void formation mechanisms and analytical predictions of the detrimental effect of porosity on the structural integrity of molded parts have been studied extensively. In contrast, knowledge of void removal strategies is very limited. In this investigation, various postfill pressure levels were applied to disk-shaped random-mat glass/epoxy parts molded at high volumetric flow rates as a method to reduce their voidage content. Quantitative image analysis over cross-sections cut from these composites revealed that significant changes in porosity concentration take place with the postfill pressure. For instance, overall void content dropped more than 70% with the application of a postfill pressure as low as 300 kPa. Other important void morphometry characteristics such as void shape, size, and spatial distribution could also be manipulated by this method. As the packing pressure increases, large voids gradually disappear, and at the same time, the small circular voids are mobilized towards radial locations near the vents. In addition to this spatial voidage gradient in the radial direction, voidage gradient also exists through the specimen thickness. It seems that higher front velocities promote the appearance of secondary flow phenomena inside the mold cavity (e.g. microfountain flow), which may explain why more voids tend to concentrate at the surface of the specimen irrespective of the postfill pressure level reached inside the mold.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

The PanCam Instrument for the ExoMars Rover

The scientific objectives of the ExoMars rover are designed to answer several key questions in the search for life on Mars. In particular, the unique subsurface drill will address some of these, such as the possible existence and stability of subsurface organics. PanCam will establish the surface geological and morphological context for the mission, working in collaboration with other context instruments. Here, we describe the PanCam scientific objectives in geology, atmospheric science, and 3-D vision. We discuss the design of PanCam, which includes a stereo pair of Wide Angle Cameras (WACs), each of which has an 11-position filter wheel and a High Resolution Camera (HRC) for high-resolution investigations of rock texture at a distance. The cameras and electronics are housed in an optical bench that provides the mechanical interface to the rover mast and a planetary protection barrier. The electronic interface is via the PanCam Interface Unit (PIU), and power conditioning is via a DC-DC converter. PanCam also includes a calibration target mounted on the rover deck for radiometric calibration, fiducial markers for geometric calibration, and a rover inspection mirror.publishersversionPeer reviewe

Creating the cultures of the future: cultural strategy, policy and institutions in Gramsci. Part one: Gramsci and cultural policy studies: some methodological reflections

Gramsci’s writings have rarely been discussed and used systematically by scholars in cultural policy studies, despite the fact that in cultural studies, from which the field emerged, Gramsci has been a major source of theoretical concepts. Cultural policy studies were, in fact, theorised as an anti-Gramscian project between the late 1980s and the early 1990s, when a group of scholars based in Australia advocated a major political and theoretical reorientation of cultural studies away from hegemony theory and radical politicisation, and towards reformist-technocratic engagement with the policy concerns of contemporary government and business. Their criticism of the ‘Gramscian tradition’ as inadequate for the study of cultural policy and institutions has remained largely unexamined in any detail for almost twenty years and seems to have had a significant role in the subsequent neglect of Gramsci’s contribution in this area of study. This essay, consisting of three parts, is an attempt to challenge such criticism and to provide an analysis of Gramsci’s writings, with the aim of proposing a more systematic contribution of his work to the theoretical development of cultural policy studies. In Part One, I question the use of the notion of ‘Gramscian tradition’ made by its critics and challenge the claim that it was inadequate for the study of cultural policy and institutions. In parts Two and Three, I consider Gramsci’s specific writings on questions of cultural strategy, policy and institutions, which have so far been overlooked by scholars, arguing that they provide further analytical insights to those offered by his more general concepts. More specifically, in Part Two, I consider Gramsci’s pre-prison writings and political practice in relation to questions of cultural strategy and institutions. I argue that the analysis of these early texts, which were written in the years in which Gramsci was active in party organisation and leadership, is fundamental not only for understanding the nature of Gramsci’s early and continued involvement with questions of cultural strategy and institutions, but also as a key for deciphering and interpreting cultural policy themes that he later developed in the prison notebooks, and which originated in earlier debates. Finally, in Part Three, I carry out a detailed analysis of Gramsci’s prison notes on questions of cultural strategy, policy and institutions, which enrich the theoretical underpinnings for critical frameworks of analysis as well as for radical practices of cultural strategy, cultural policy-making and cultural organisation. I then answer the question of whether Gramsci’s insights amount to a theory of cultural policy

Investigating the role of customers’ perceptions of employee effort and justice in service recovery

Purpose: The purpose of this paper is, first, to identify the relationship, if any, between customers’ perceptions of justice (functional element) and employee effort (symbolic element) and their effects on satisfaction and loyalty in the context of service recovery and, second, to determine the impact of cross-cultural differences on these relationships. Design/methodology/approach: Survey data from actual customers were gathered in three countries (n = 414) and analyzed using structural equation modeling to test the proposed hypotheses. Findings: The results demonstrate the role of the constructs of perceived employee effort and perceived justice in influencing post-recovery satisfaction and loyalty across cultures. While perceived justice is valued across cultures, customers from feminine (masculine) cultures require more (less) employee effort to influence post-recovery satisfaction positively. Customers from low (high) uncertainty cultures are more (less) willing to give the provider another chance after a service recovery. Research limitations/implications: The study shows that both functional and symbolic elements of service recovery are important determinants of customer satisfaction and loyalty and that their influence can be significant in a cross-cultural context. Practical implications: International service managers must consider the nature of cultural differences in their markets to develop and implement tailored recovery strategies that can result in satisfied customers. Originality/value: This study is the first to integrate the functional and symbolic elements of service recovery, their impact on customers’ behavioral responses and the influence of cultural variations

Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC

A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions

The performance of the jet trigger for the ATLAS detector during 2011 data taking

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction

Measurement of the cross section for isolated-photon plus jet production in pp collisions at √s=13 TeV using the ATLAS detector

The dynamics of isolated-photon production in association with a jet in proton–proton collisions at a centre-of-mass energy of 13 TeV are studied with the ATLAS detector at the LHC using a dataset with an integrated luminosity of 3.2 fb−1. Photons are required to have transverse energies above 125 GeV. Jets are identified using the anti- algorithm with radius parameter and required to have transverse momenta above 100 GeV. Measurements of isolated-photon plus jet cross sections are presented as functions of the leading-photon transverse energy, the leading-jet transverse momentum, the azimuthal angular separation between the photon and the jet, the photon–jet invariant mass and the scattering angle in the photon–jet centre-of-mass system. Tree-level plus parton-shower predictions from Sherpa and Pythia as well as next-to-leading-order QCD predictions from Jetphox and Sherpa are compared to the measurements

Measurements of fiducial cross-sections for t\bart production with one or two additional b-jets in pp collisions at √s =8 TeVusing the ATLAS detector

Fiducial cross-sections for $t\bar{t}$ production with one or two additional $b$-jets are reported, using an integrated luminosity of 20.3 fb$^{-1}$ of proton--proton collisions at a centre-of-mass energy of 8 TeV at the Large Hadron Collider, collected with the ATLAS detector. The cross-section times branching ratio for $t\bar{t}$ events with at least one additional $b$-jet is measured to be 950 $\pm$ 70 (stat.) $^{+240}_{-190}$ (syst.) fb in the lepton-plus-jets channel and 50 $\pm$ 10 (stat.) $^{+15}_{-10}$ (syst.) fb in the $e \mu$ channel. The cross-section times branching ratio for events with at least two additional $b$-jets is measured to be 19.3 $\pm$ 3.5 (stat.) $\pm$ 5.7 (syst.) fb in the dilepton channel ($e \mu$,\,$\mu\mu$, and \,$ee$) using a method based on tight selection criteria, and 13.5 $\pm$ 3.3 (stat.) $\pm$ 3.6 (syst.) fb using a looser selection that allows the background normalisation to be extracted from data. The latter method also measures a value of 1.30 $\pm$ 0.33 (stat.) $\pm$ 0.28 (syst.)\% for the ratio of $t\bar{t}$ production with two additional $b$-jets to $t\bar{t}$ production with any two additional jets. All measurements are in good agreement with recent theory predictions.Comment: 41 pages plus author list + cover page (58 total), 9 Figures, 16 tables, submitted to EPJC, all figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2014-10

Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector

This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be: σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented