MARKET POWER AND OFF-INVOICE TRADE PROMOTIONS IN THE US: AN EMPIRICAL INVESTIGATION

This article employs a Tobit model to examine whether the market power of manufacturers and retailers influence trade promotion decisions in the US food sector. Greater retailer market power increases allocation of funds to off-invoice trade promotions. We find evidence that the balance of power favors food retailers.Marketing,

Characterizing the radial oxygen abundance distribution in disk galaxies

We examine the possible dependence of the radial oxygen abundance distribution on non-axisymmetrical structures (bar/spirals) and other macroscopic parameters such as the mass, the optical radius R25, the color g-r, and the surface brightness of the galaxy. A sample of disk galaxies from the CALIFA DR3 is considered. We adopted the Fourier amplitude A2 of the surface brightness as a quantitative characteristic of the strength of non-axisymmetric structures in a galactic disk, in addition to the commonly used morphologic division for A, AB, and B types based on the Hubble classification. To distinguish changes in local oxygen abundance caused by the non-axisymmetrical structures, the multiparametric mass--metallicity relation was constructed as a function of parameters such as the bar/spiral pattern strength, the disk size, color index g-r in the SDSS bands, and central surface brightness of the disk. The gas-phase oxygen abundance gradient is determined by using the R calibration. We find that there is no significant impact of the non-axisymmetric structures such as a bar and/or spiral patterns on the local oxygen abundance and radial oxygen abundance gradient of disk galaxies. Galaxies with higher mass, however, exhibit flatter oxygen abundance gradients in units of dex/kpc, but this effect is significantly less prominent for the oxygen abundance gradients in units of dex/R25 and almost disappears when the inner parts are avoided. We show that the oxygen abundance in the central part of the galaxy depends neither on the optical radius R25 nor on the color g-r or the surface brightness of the galaxy. Instead, outside the central part of the galaxy, the oxygen abundance increases with g-r value and central surface brightness of the disk.Comment: 11 pages, 6 figures; accepted for publication in A&

Calibration of radii and masses of open clusters with a simulation

Context: A recent new approach to apply a simple dynamical mass estimate of tidally limited star clusters is based on the identification of the tidal radius in a King profile with the dynamical Jacobi radius. The application to an unbiased open cluster catalogue yields significantly higher cluster masses compared to the classical methods. Aims: We quantify the bias in the mass determination as function of projection direction and cluster age by analysing a simulated star cluster. Methods: We use direct $N$-body simulations of a star cluster including stellar evolution in an analytic Milky Way potential and apply a best fit to the projected number density of cluster stars. Results: We obtain significantly overestimated star cluster masses which depend strongly on the viewing direction. The overestimation is typically in the range of 10-50 percent and reaches a factor of 3.5 for young clusters. Mass segregation reduces the derived limiting radii systematically.Comment: 9 pages, 10+1 figures, accepted by Astronomy and Astrophysic

Transfer of autocollimator calibration for use with scanning gantry profilometers for accurate determination of surface slope and curvature of state of the art x ray mirrors

X ray optics, desired for beamlines at free electron laser and diffraction limited storage ring x ray light sources, must have almost perfect surfaces, capable of delivering light to experiments without significant degradation of brightness and coherence. To accurately characterize such optics at an optical metrology lab, two basic types of surface slope profilometers are used the long trace profilers LTPs and nanometer optical measuring NOM like angular deflectometers, based on electronic autocollimator AC ELCOMAT 3000. The inherent systematic errors of the instrument s optical sensors set the principle limit to their measuring performance. Where autocollimator of a NOM like profiler may be calibrated at a unique dedicated facility, this is for a particular configuration of distance, aperture size, and angular range that does not always match the exact use in a scanning measurement with the profiler. Here we discuss the developed methodology, experimental set up, and numerical methods of transferring the calibration of one reference AC to the scanning AC of the Optical Surface Measuring System OSMS , recently brought to operation at the ALS Xray Optics Laboratory. We show that precision calibration of the OSMS performed in three steps, allows us to provide high confidence and accuracy low spatial frequency metrology and not print into measurements the inherent systematic error of tool in use. With the examples of the OSMS measurements with a state of the art x ray aspherical mirror, available from one of the most advanced vendors of X ray optics, we demonstrate the high efficacy of the developed calibration procedure. The results of our work are important for obtaining high reliability data, needed for sophisticated numerical simulations of beamline performance and optimization of beamline usage of the optics. This work was supported by the U. S. Department of Energy under contract number DE AC02 05CH1123

La inserción económica de personas con dificultades añadidas en el Ayuntamiento de Girona : una estrategia para la cohesión y el desarrollo local

En este artículo se expone la experiencia de un dispositivo municipal, cuyo objetivo básico y fundamental es la inserción económica a través del empleo, como un instrumento de inserción social y de lucha contra la exclusión, dirigido a personas con dificultades especiales. Su importancia radica en ser un dispositivo único en el municipio de Girona para intermediar a favor de personas, que sin un dispositivo específico, como es el DIE (Dispositivo de Inserción Económica) les sería muy difícil acceder al mundo del empleo. Esta sería una de la premisas básicas bajo las cuales se trabaja desde este dispositivo; otras serían: la creación de escenarios de inserción, formación, acompañamiento, orientación, desde dentro de esos mismos escenarios; la oferta de fórmulas de inserción en empresas ordinarias o bien en mercados de trabajo protegido, hasta concretarse en doce modalidades distintas de inserción y la última premisa es la intervención multidimensional sobre la persona en otras esferas de la vida, ya que aparte del estricto mundo de la ocupación, existen otros factores que determinan la situación socioeconómica de las personas y su falta de inserción social.This article exposes the experience of a municipal device, whose basic and fundamental objective is the economic insertion through employment, as an instrument of social insertion and struggle against exclusion, aimed at people with special difficulties. Its importance lies in being a unique device in the municipality of Girona to mediate in favor of people, who without a specific device, such as the DIE (Economic Insertion Device) would find it very difficult to access the world of employment. This would be one of the basic premises under which we work from this device; others would be: the creation of insertion scenarios, training, accompaniment, orientation, from within those same scenarios; the offer of insertion formulas in ordinary companies or in protected labour markets, until materializing in twelve different insertion modalities, and the last premise is the multidimensional intervention on the person in other spheres of life, since apart from the strict world of the occupation, there are other factors that determine the socioeconomic situation of the people and their lack of social insertion

Towards predicting post-editing productivity

Machine translation (MT) quality is generally measured via automatic metrics, producing scores that have no meaning for translators who are required to post-edit MT output or for project managers who have to plan and budget for transla- tion projects. This paper investigates correlations between two such automatic metrics (general text matcher and translation edit rate) and post-editing productivity. For the purposes of this paper, productivity is measured via processing speed and cognitive measures of effort using eye tracking as a tool. Processing speed, average fixation time and count are found to correlate well with the scores for groups of segments. Segments with high GTM and TER scores require substantially less time and cognitive effort than medium or low-scoring segments. Future research involving score thresholds and confidence estimation is suggested

High resolution simulations of unstable modes in a collisionless disc

We present N-body simulations of unstable spiral modes in a dynamically cool collisionless disc. We show that spiral modes grow in a thin collisionless disk in accordance with the analytical perturbation theory. We use the particle-mesh code SUPERBOX with nested grids to follow the evolution of unstable spirals that emerge from an unstable equilibrium state. We use a large number of particles (up to 40 million particles) and high-resolution spatial grids in our simulations (128^3 cells). These allow us to trace the dynamics of the unstable spiral modes until their wave amplitudes are saturated due to nonlinear effects. In general, the results of our simulations are in agreement with the analytical predictions. The growth rate and the pattern speed of the most unstable bar-mode measured in N-body simulations agree with the linear analysis. However the parameters of secondary unstable modes are in lesser agreement because of the still limited resolution of our simulations.Comment: 11 pages, 8 figures in 22 files, A&A in print: Oct. 1st 200

Simulation of the loss-cone instability in spherical systems. I. Dominating harmonic potential

A new so-called `gravitational loss-cone instability' in stellar systems has recently been investigated theoretically in the framework of linear perturbation theory and proved to be potentially important in understanding the physical processes in centres of galaxies, star clusters, and the Oort comet cloud. Using N-body simulations of a toy model, we confirm previous findings for the harmonic dominating potential and go beyond the linear theory. Unlike the well-known instabilities, the new one shows no notable change in the spherical geometry of the cluster, but it significantly accelerates the speed of diffusion of particles in phase space leading to an early instability saturation.Comment: 6 pages, 9 figures, MNRAS accepte

Extensive study of nuclear uncertainties and their impact on the r-process nucleosynthesis in neutron star mergers

Theoretically predicted yields of elements created by the rapid neutron capture (r-) process carry potentially large uncertainties associated with incomplete knowledge of nuclear properties as well as approximative hydrodynamical modelling of the matter ejection processes. We present an in-depth study of the nuclear uncertainties by systematically varying theoretical nuclear input models that describe the experimentally unknown neutron-rich nuclei. This includes two frameworks for calculating the radiative neutron capture rates and six, four and four models for the nuclear masses, $\beta$-decay rates and fission properties, respectively. Our r-process nuclear network calculations are based on detailed hydrodynamical simulations of dynamically ejected material from NS-NS or NS-BH binary mergers plus the secular ejecta from BH-torus systems. The impact of nuclear uncertainties on the r-process abundance distribution and early radioactive heating rate is found to be modest (within a factor $\sim 20$ for individual $A>90$ nuclei and a factor 2 for the heating rate), however the impact on the late-time heating rate is more significant and depends strongly on the contribution from fission. We witness significantly larger sensitivity to the nuclear physics input if only a single trajectory is used compared to considering ensembles of $\sim$200-300 trajectories, and the quantitative effects of the nuclear uncertainties strongly depend on the adopted conditions for the individual trajectory. We use the predicted Th/U ratio to estimate the cosmochronometric age of six metal-poor stars to set a lower limit of the age of the Galaxy and find the impact of the nuclear uncertainties to be up to 2 Gyr.Comment: 26 pages, 22 figures, submitted to MNRA