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Lloret, E., Picouet, P. A., Trbojevich, R., & Fernandez, A. (2016). Colour stability of cooked ham packed under modified atmospheres in polyamide nanocomposite blends. LWT-Food Sci. Technol., 66, 582–589.
Abstract: Two novel blends containing a low-density polyethylene (LDPE) and a neat polyamide (PA) or a polyamide nanocomposite (PAN) layers were fabricated and their technological potential was evaluated during the refrigeration of cooked ham in modified atmospheres (MAP). Nanoclays were homogeneously distributed and nearly exfoliated, and they lowered significantly the oxygen transmission rate (OTR) of the PAN films. Due to the lower OTR, the headspace oxygen level in PAN pouches do not rise above 0.26% but it approached 2% in PA pouches at day 20. The residual oxygen levels were key for colour change during MAP storage of cooked ham. Cooked ham redness and reflectivity were stable during 27 days in PAN pouches while a strong colour deterioration took place after day 7 in PA pouches. Other parameters such as moisture content and water activity remained unaltered, and pH development was related to microbial growth and independent of the packaging polymer. The evolution of cooked ham colour in PAN was comparable to a high-barrier commercial polymer, and was acceptable for commercial sale for 27 days, showing excellent perspectives for polyamide nanocomposites in the storage of cooked ham.
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Lloret, E., Fernandez, A., Trbojevich, R., Arnau, J., & Picouet, P. A. (2016). Relevance of nanocomposite packaging on the stability of vacuum-packed dry cured ham. Meat Sci., 118, 8–14.
Abstract: In this study effects of a novel high barrier multilayer polyamide film containing dispersed nanoclays (PAN) on the stability of vacuum packed dry-cured ham were investigated during 90 days refrigerated storage in comparison with non-modified multilayer polyamide (PA) and a commercial high barrier film. Characteristic bands of the mineral in FT-IR spectra confirmed the presence of nanoclays in PAN, enhancing oxygen transmission barrier properties and UV protection. Packaging in PAN films did not originate significant changes on colour or lipid oxidation during prolonged storage of vacuum-packed dry-cured ham. Larger oxygen transmission rates in PA films caused changes in CIE b* during refrigerated storage. Ham quality was not affected by light exposition during 90 days and only curing had a significant benefit on colour and TBARS, being cured samples more stable during storage in all the packages used. Packaging of dry-cured ham in PAN was equivalent to commercial high barrier films.
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Liu, S., Bogard, F., Cornebise, P., Faus-Golfe, A., Fuster-Martinez, N., Griesmayer, E., et al. (2016). In vacuum diamond sensor scanner for beam halo measurements in the beam line at the KEK Accelerator Test Facility. Nucl. Instrum. Methods Phys. Res. A, 832, 231–242.
Abstract: The investigation of beam halo transverse distributions is important for the understanding of beam losses and the control of backgrounds in Future Linear Colliders (FLC). A novel in vacuum diamond sensor (DSv) scanner with four strips has been designed and developed for the investigation of the beam halo transverse distributions and also for the diagnostics of Compton recoil electrons after the interaction point (IP) of ATF2, a low energy (1.3 GeV) prototype of the final focus system for the ILC and CLIC linear collider projects. Using the DSv, a dynamic range of similar to 10(6) has been successfully demonstrated and confirmed for the first time in simultaneous beam core (similar to 10(6) electrons) and beam halo (similar to 10(3) electrons) measurements at ATF2. This report presents the characterization, performance studies and tests of diamond sensors using an a source, as well as using the electron beams at PHIL, a low energy (<5 MeV) photo-injector at LAL, and at ATF2. First beam halo measurement results using the DSv at ATF2 with different beam intensities and vacuum levels are also presented. Such measurements not only allow one to evaluate the different sources of beam halo generation but also to define the requirements for a suitable collimation system to be installed at ATF2, as well as to optimize its performance during future operation.
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Liem, S., Bertone, G., Calore, F., Ruiz de Austri, R., Tait, T. M. P., Trotta, R., et al. (2016). Effective field theory of dark matter: a global analysis. J. High Energy Phys., 09(9), 077–22pp.
Abstract: We present global fits of an effective field theory description of real, and complex scalar dark matter candidates. We simultaneously take into account all possible dimension 6 operators consisting of dark matter bilinears and gauge invariant combinations of quark and gluon fields. We derive constraints on the free model parameters for both the real (five parameters) and complex (seven) scalar dark matter models obtained by combining Planck data on the cosmic microwave background, direct detection limits from LUX, and indirect detection limits from the Fermi Large Area Telescope. We find that for real scalars indirect dark matter searches disfavour a dark matter particle mass below 100 GeV. For the complex scalar dark matter particle current data have a limited impact due to the presence of operators that lead to p-wave annihilation, and also do not contribute to the spin-independent scattering cross-section. Although current data are not informative enough to strongly constrain the theory parameter space, we demonstrate the power of our formalism to reconstruct the theoretical parameters compatible with an actual dark matter detection, by assuming that the excess of gamma rays observed by the Fermi Large Area Telescope towards the Galactic centre is entirely due to dark matter annihilations. Please note that the excess can very well be due to astrophysical sources such as millisecond pulsars. We find that scalar dark matter interacting via effective field theory operators can in principle explain the Galactic centre excess, but that such interpretation is in strong tension with the non-detection of gamma rays from dwarf galaxies in the real scalar case. In the complex scalar case there is enough freedom to relieve the tension.
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Liddick, S. N., Spyrou, A., Crider, B. P., Naqvi, F., Larsen, A. C., Guttormsen, M., et al. (2016). Experimental Neutron Capture Rate Constraint Far from Stability. Phys. Rev. Lett., 116(24), 242502–6pp.
Abstract: Nuclear reactions where an exotic nucleus captures a neutron are critical for a wide variety of applications, from energy production and national security, to astrophysical processes, and nucleosynthesis. Neutron capture rates are well constrained near stable isotopes where experimental data are available; however, moving far from the valley of stability, uncertainties grow by orders of magnitude. This is due to the complete lack of experimental constraints, as the direct measurement of a neutron-capture reaction on a short-lived nucleus is extremely challenging. Here, we report on the first experimental extraction of a neutron capture reaction rate on Ni-69, a nucleus that is five neutrons away from the last stable isotope of Ni. The implications of this measurement on nucleosynthesis around mass 70 are discussed, and the impact of similar future measurements on the understanding of the origin of the heavy elements in the cosmos is presented.
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