Investigating Canadian Chicken Importers' Preferences Towards TRQ Import Licensing Mechanisms

The Agreement on Agriculture ratified at the end of the Uruguay Round of WTO negotiations called for the conversion of non-tariff barriers to trade into bound tariffs. This tariffication would have resulted in excessively high tariffs, which would have threatened historic market access levels if not for WTO member countries agreeing to introduce tariff-rate quotas (TRQs). TRQs are two-tier tariffs. Imports below an agreed quota are taxed at a usually low (or zero) in-quota tariff rate while imported commodities in excess of the quota level are taxed at the higher (often prohibitive) over-quota tariff rate. In the process of implementing TRQs, WTO members failed to explicitly regulate TRQ administration procedures. As a result, numerous administration procedures for allocating import licenses were developed in many countries. Importing activities in the Canadian chicken industry have been regulated with a TRQ since 1995. Firms holding the right to import chicken products at the in-quota tariff can potentially enjoy significant rents due to the spread between domestic and world prices. The magnitude of these rents depends upon a number of domestic factors such as market concentration in the processing and retail sectors, production technology, farm output regulation, and so on. This analysis evaluates the preferences of Canadian chicken importers towards TRQ import licensing mechanisms and provides insights about importers’ attitudes towards Canadian trade policy in the chicken sector.Agricultural and Food Policy, International Relations/Trade,

Discrete curvature approximations and segmentation of polyhedral surfaces

The segmentation of digitized data to divide a free form surface into patches is one of the key steps required to perform a reverse engineering process of an object. To this end, discrete curvature approximations are introduced as the basis of a segmentation process that lead to a decomposition of digitized data into areas that will help the construction of parametric surface patches. The approach proposed relies on the use of a polyhedral representation of the object built from the digitized data input. Then, it is shown how noise reduction, edge swapping techniques and adapted remeshing schemes can participate to different preparation phases to provide a geometry that highlights useful characteristics for the segmentation process. The segmentation process is performed with various approximations of discrete curvatures evaluated on the polyhedron produced during the preparation phases. The segmentation process proposed involves two phases: the identification of characteristic polygonal lines and the identification of polyhedral areas useful for a patch construction process. Discrete curvature criteria are adapted to each phase and the concept of invariant evaluation of curvatures is introduced to generate criteria that are constant over equivalent meshes. A description of the segmentation procedure is provided together with examples of results for free form object surfaces

Muon Anomaly from Lepton Vacuum Polarization and The Mellin--Barnes Representation

We evaluate, analytically, a specific class of eighth--order and tenth--order QED contributions to the anomalous magnetic moment of the muon. They are generated by Feynman diagrams involving lowest order vacuum polarization insertions of leptons $l=e,\mu$, and $\tau$. The results are given in the form of analytic expansions in terms of the mass ratios $m_e/m_\mu$ and $m_\mu/m_\tau$. We compute as many terms as required by the error induced by the present experimental uncertainty on the lepton masses. We show how the Mellin--Barnes integral representation of Feynman parametric integrals allows for an easy analytic evaluation of as many terms as wanted in these expansions and how its underlying algebraic structure generalizes the standard renormalization group properties. We also discuss the generalization of this technique to the case where two independent mass ratios appear. Comparison with previous numerical and analytic evaluations made in the literature, whenever pertinent, are also made.Comment: v2, minor changes in the introduction, typos corrected, two references added; to appear in Phys. Rev.

Forward Physics at the LHC: within and beyond the Standard Model

We review the detection capabilities in the forward direction of the various LHC experiments together with the associated physics programme. A selection of measurements accessible with near-beam instrumentation in various sectors (and extensions) of the Standard Model (SM) is outlined, including QCD (diffractive and elastic scattering, low-x parton dynamics, hadronic Monte Carlos for cosmic-rays), electroweak processes in gamma-gamma interactions, and Higgs physics (vector-boson-fusion and central exclusive production).Comment: 9 pages, 18 figs. Lectures given at the LAWHEP'07 School (Sao Miguel das Missoes, Brazil, 3-7 Dec 2007) to appear in Braz. J. Phys. Also presented in HLPW08 (Spa, Belgium, 6-8 Mar 2008) AIP Conf. Proceeds, to appear; and in HANUC European Grad. School (Jyvaskyla, Finland, 25-29 Aug. 2008

Single and multiphase CFD approaches for modelling partially baffled stirred vessels: comparison of experimental data with numerical predictions

Whilst the use of CFD to study mixing vessels is now common-place, there are still many specialised applications that are yet to be addressed. Here we present CFD and PIV results for a hydrodynamic study of a partially baffled vessel with a free surface. The standard k.ε and SSG Reynolds Stress turbulence models are used and the numerical predictions of the mean flow field are compared with experimental data for single phase modelling. At low rotation rates a flat free surface is observed and the flow is simulated using a single phase model, whilst at high rotation rates an Eulerian–Eulerian multiphase model is used to capture the free surface location, even under conditions when gas is drawn down to the impeller. It is shown that there are significant transient effects that mean many of the “rules of thumb” that have been developed for fully baffled vessels must be revisited. In particular such flows have central vortices that are unsteady and complex, transient flow-induced vortical structures generated by the impeller–baffle interactions and require a significant number of simulated agitator rotations before meaningful statistical analysis can be performed. Surprisingly, better agreement between CFD and experimental data was obtained using the k.ε than the SSG Reynolds stress model. The multiphase inhomogeneous approach used here with simplified physics assumptions gives good agreement for power consumption, and with PIV measurements with flat and deformed free surfaces, making this affordable method practical to avoid the erroneous modelling assumption of a flat free surface often made in such cases