70 research outputs found

    Vector meson production and nucleon resonance analysis in a coupled-channel approach for energies m_N < sqrt(s) < 2 GeV II: photon-induced results

    Full text link
    We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states gamma N, pi N, 2 pi N, eta N, K Lambda, K Sigma, and omega N for energies from the nucleon mass up to sqrt(s) = 2 GeV. In this analysis we find strong evidence for the resonances P_{31}(1750), P_{13}(1900), P_{33}(1920), and D_{13}(1950). The omega N production mechanism is dominated by large P_{11}(1710) and P_{13}(1900) contributions. In this second part we present the results on the photoproduction reactions and the electromagnetic properties of the resonances. The inclusion of all important final states up to sqrt(s) = 2 GeV allows for estimates on the importance of the individual states for the GDH sum rule.Comment: 41 pages, 26 figures, discussion extended, typos corrected, references updated, to appear in Phys. Rev.

    Driven to excess? Linking calling, character and the (mis)behaviour of marketers

    Get PDF
    We are presently at a point of unique circumstantial convergence where recession, an increased emphasis on business ethics, and marketer’s reluctance to accept shifting social agendas have combined to identify the need for a new approach to marketing. Using concepts from the human resources, marketing and psychology literatures, and especially Erich Fromm’s ideas concerning economic character, this paper posits that marketers – as a professional community – are driven to promote consumerist outcomes; victims of an automaton amalgam of calling and character. The analysis suggests the vulnerability of both marketer and consumer are mutually reinforcing and that we need, somehow, to break this damaging cycle of dependence. We know little, however, about how marketers think and feel about their discipline, so this paper also promotes an agenda for marketer behaviour research, as a countervailing balance to a currently disproportionate focus on the consumer

    GW190814: gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object

    Get PDF
    We report the observation of a compact binary coalescence involving a 22.2–24.3 Me black hole and a compact object with a mass of 2.50–2.67 Me (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO’s and Virgo’s third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of - + 241 45 41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, - + 0.112 0.009 0.008, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to ïżœ0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries

    Lower-Order Aerodynamic Loads Modeling of a Maneuvering Generic Fighter Using DDES Simulations

    Get PDF
    Unforeseen nonlinear aerodynamic behavior and/or fluid-structure interactions have affected the development of nearly every major fighter program since 1960. The development cost of each of these aircraft could have been drastically reduced if these aerodynamic issues had been identified earlier in the design process. Therefore, a high-fidelity computational tool capable of reliably predicting or identifying configurations susceptible to handling quality instabilities prior to flight test would be of great interest to the stability and control community. The United States Air Force Academy Modeling and Simulation Research Center and the United States Air Force Seek Eagle Office have initiated a joint effort to develop nonlinear lower-order aerodynamic loads models from unsteady CFD solutions. A key step in the process is to perform “training maneuvers,” which are dynamic CFD simulations designed to excite the relevant nonlinear flow physics. A reduced-order model is then built using SIDPAC, a regression based modeling technique designed specifically for aircraft system identification. The approach is validated for an aircraft configuration with a known aerodynamic instability that occurs well within the flight envelope. The dynamic CFD simulations can reliably predict this instability for frequencies ranging from 1.43 to 17.1 Hertz. In addition, an aerodynamic model trained using a varying frequency chirp maneuver was then used to predict constant frequency aerodynamic loads at conditions where strongly nonlinear aerodynamic behavior occurred

    Player account-based gambling: potentials for behaviour-based research methodologies

    No full text
    The emergence of player account-based gambling is a result of escalating technological sophistication and the incorporation of these developments into gambling. This term refers to gambling from a centralized account that is linked to an identified individual. Player account-based gambling is increasingly being utilized for multiple forms of Internet, mobile and land-based gambling through player cards and user-names. Player accounts track and store a wealth of data on gambling behaviour and related activities. Gambling research has been justifiably criticized for its reliance on self-report rather than behavioural measures. Research analysing player account data may advance conceptual models, identify behavioural risk factors for problem gambling and evaluate and guide effective policy and responsible gambling programmes. Although research utilizing player account data has unique limitations, it offers considerable benefits for researchers, operators and regulators. Research methodology incorporating the use of player account data stands to make significant contributions to the gambling field
    • 

    corecore