1,245 research outputs found

    The VVV-SkZ pipeline: an automatic PSF-fitting photometric pipeline for the VVV survey

    Get PDF
    We present the VVV-SkZ_pipeline, a DAOPHOT-based photometric pipeline, created to perform PSF-fitting photometry of "VISTA Variables in the V\'ia L\'actea" (VVV) ESO Public Survey data. The pipeline replaces the user avoiding repetitive interaction in all the operations, retaining all of the benefits of the power and accuracy of the DAOPHOT suite. The pipeline provides an astrometrized photometric catalog reliable up to more than 2 magnitudes brighter than the saturation limit, where other techniques fail. It also produces deeper and more accurate photometry. These achievements allow the VVV-SkZ_pipeline to produce data well anchored to the selected standard photometric system and analyze important phenomena (i.e. TRGB, RGB slope, HB morphology, RR Lyrae), that other methods are not able to manage.Comment: Accepted by RevMexAA for vol. 49, n.2, October 201

    Quantifying MNC Geographic Scope

    Get PDF
    This paper proposes a multidimensional index of regional and global orientation which can be used in confirmatory studies with econometric methodologies. Unlike extant measures, the index is objectively scaled and controls for home country orientation and market size differences. The index is shown to be consistent with models of internationalization that incorporate different assumptions about strategic choice and global competition. Preliminary results show that large multinationals follow home region oriented internationalization paths, although much of the regional effect reported by previous studies in fact reflects strong home country biases. Keywords: globalization; regional integration; global strategy; regional strategy; local strategy; triad; liability of foreignnes

    Earlier Research and the Role of Frictions

    Get PDF
    This paper provides a counterpoint to Buckley and Hashai’s paper “Is competitive advantage a necessary condition for the emergence of the Multinational Enterprise?”. We agree with their conclusion that it is, in fact, not a necessary condition, but argue that the theoretical reasons behind this are different and more diverse than the ones they propose. We suggest that much extant economic theory is in fact consistent with their view that firms may internationalize without owning or achieving competitive advantages, and model various other ways in which imperfections can drive their overall result. We strongly applaud Buckley and Hashai’s attempt to add more rigor to International Business theory and call for future work to extend this debate

    Corporate social responsibility in the global value chain: a bargaining perspective

    Get PDF
    Breaches of corporate social responsibility (CSR) in global value chains (GVCs) pose a managerial challenge for multinational enterprises (MNEs) and threaten both their reputations and global sustainability. While an MNE-centric perspective on these issues has dominated existing international business research, we show that a dynamic view of bargaining among actors in the GVC can yield novel insights. We draw on coalitional game theory and develop a model where an MNE collaborates, monitors, and negotiates prices with a supplier whose CSR breaches may be revealed by the MNE, external agents, or remain hidden. Our model illustrates how MNEs may face a hold-up problem when irresponsible actions by suppliers are made public, and the suppliers have the power to engage in opportunistic renegotiation. Interestingly, we show that greater monitoring by MNEs, if not combined with specific strategies, can have negative consequences by weakening the MNE's bargaining position and, in some cases, even prompting more irresponsible actions by the suppliers. Our model advances international business research on GVC sustainability and has important implications for managers and researchers alike

    Optical reconfiguration and polarization control in semi-continuous gold films close to the percolation threshold

    Get PDF
    Controlling and confining light by exciting plasmons in resonant metallic nanostructures is an essential aspect of many new emerging optical technologies. Here we explore the possibility of controllably reconfiguring the intrinsic optical properties of semi-continuous gold films, by inducing permanent morphological changes with a femtosecond (fs)-pulsed laser above a critical power. Optical transmission spectroscopy measurements show a correlation between the spectra of the morphologically modified films and the wavelength, polarization, and the intensity of the laser used for alteration. In order to understand the modifications induced by the laser writing, we explore the near-field properties of these films with electron energy-loss spectroscopy (EELS). A comparison between our experimental data and full-wave simulations on the exact film morphologies hints toward a restructuring of the intrinsic plasmonic eigenmodes of the metallic film by photothermal effects. We explain these optical changes with a simple model and demonstrate experimentally that laser writing can be used to controllably modify the optical properties of these semi-continuous films. These metal films offer an easy-to-fabricate and scalable platform for technological applications such as molecular sensing and ultra-dense data storage.Comment: Supplementary materials available upon request ([email protected]

    Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators

    Get PDF
    We present wide-field JHKS photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the Two Micron All-Sky Survey photometric system. Differential reddening corrections and statistical field star decontamination are employed for all of these clusters before fitting fiducial sequences to the cluster red giant branches (RGBs). Observed values and uncertainties are reported for several photometric features, including the magnitude of the RGB bump, tip, the horizontal branch (HB) and the slope of the upper RGB. The latest spectroscopically determined chemical abundances are used to build distance- and reddening-independent relations between observed photometric features and cluster metallicity, optimizing the sample size and metallicity baseline of these relations by supplementing our sample with results from the literature.We find that the magnitude difference between the HB and the RGB bump can be used to predict metallicities, in terms of both iron abundance [Fe/H] and global metallicity [M/H], with a precision of better than 0.1 dex in all three near-IR bandpasses for relatively metal-rich ([M/H] −1) clusters. Meanwhile, both the slope of the upper RGB and the magnitude difference between the RGB tip and bump are useful metallicity indicators over the entire sampled metallicity range (−2 [M/H] 0) with a precision of 0.2 dex or better, despite model predictions that the RGB slope may become unreliable at high (near-solar) metallicities. Our results agree with previous calibrations in light of the relevant uncertainties, and we discuss implications for clusters with controversial metallicities as well as directions for further investigation
    • 

    corecore