Generating Equidistributed Meshes in 2D via Domain Decomposition

In this paper we consider Schwarz domain decomposition applied to the generation of 2D spatial meshes by a local equidistribution principle. We briefly review the derivation of the local equidistribution principle and the appropriate choice of boundary conditions. We then introduce classical and optimized Schwarz domain decomposition methods to solve the resulting system of nonlinear equations. The implementation of these iterations are discussed, and we conclude with numerical examples to illustrate the performance of the approach

Canada - Export Credits and Loan Guarantees for Regional Aircraft (WT/DS222/R) A Comment

This panel report represents another installment in the long-standing litigation between Canada and Brazil over subsidization of sales of commuter jets by both countries. The report addresses a set of claims by Brazil closely related to prior claims concerning the practices of the Export Development Corporation as well as industrial policy entities in the Canadian province of Quebec. Brazil specifically challenged certain recent transactions where these federal and provincial entities provided certain kinds of financing assistance in connection with the sale of Bombardier aircraft (namely to Air Wisconsin, Atlantic Coast Airlines, Comair, Kendell, and Air Nostrum). For the most part the panel applied existing jurisprudence on export subsidies to the factual record. In particular, the panel applied a "private investor principle”, verifying in all instances whether the conditions that were granted by the export development and industrial policy agencies were more favorable than the conditions that were available from alternative private source

United States - Section 211 Omnibus Appropriations Act of 1998 (WT/DS176/AB/R) A Comment

As usual the authors have divided their labor, based on expertise. In particular, the economic analysis in section 4 was the responsibility of Damien Neven; Robert Howse's own understanding of the costs and benefits of international trade law rules with respect to intellectual property protection in general depends on a rather different framework for analysing the problem. However, in so far as the legal and economic analysis of the Havana Club case itself is concerned, which deals only with trademarks as a form of IP protection, the authors are in agreemen

United States - Tax treatment for "Foreign Sales Corporations” Recourse to Arbitration by the United States under Article 22.6 of the DSU and Article 4.11 of the SCM Agreement (WT/DS108/ARB) A Comment

Some of the legal analysis in this study derives from joint work between Robert Howse and Susan Esserman on this ruling, "Trade disputes quire fairer arbitration,” FT.com, Sep 12, 2002 This chapter discusses the decision by the arbitrator on suspension of concessions ("retaliation”) in the dispute between the US and the EU regarding the tax treatment of offshore corporate income under US legislation. By way of background, the first part of the chapter (section 2) describes the operation of the US scheme, including as revised after the first round of WTO ruling

Phase separation and rotor self-assembly in active particle suspensions

Adding a non-adsorbing polymer to passive colloids induces an attraction between the particles via the `depletion' mechanism. High enough polymer concentrations lead to phase separation. We combine experiments, theory and simulations to demonstrate that using active colloids (such as motile bacteria) dramatically changes the physics of such mixtures. First, significantly stronger inter-particle attraction is needed to cause phase separation. Secondly, the finite size aggregates formed at lower inter-particle attraction show unidirectional rotation. These micro-rotors demonstrate the self assembly of functional structures using active particles. The angular speed of the rotating clusters scales approximately as the inverse of their size, which may be understood theoretically by assuming that the torques exerted by the outermost bacteria in a cluster add up randomly. Our simulations suggest that both the suppression of phase separation and the self assembly of rotors are generic features of aggregating swimmers, and should therefore occur in a variety of biological and synthetic active particle systems.Comment: Main text: 6 pages, 5 figures. Supplementary information: 5 pages, 4 figures. Supplementary movies available from httP://www.pnas.org/lookup/suppl/doi:10.1073/pnas.1116334109/-/DCSupplementa

Electrochemically-triggered spatially and temporally resolved multi-component gels

Spatial control over gelation with low molecular weight gelators is possible using an electrochemically-driven pH triggering method. Gelation occurs at the electrode surface. We show here that composition control in multi-component low molecular weight hydrogels can also be achieved, allowing simultaneous spatial, temporal and compositional control

Synthesis and antibacterial profiles of targeted triclosan derivatives

There is an ongoing urgent need for new targeted antibacterial com pounds with novel mechanisms of action for the treatment of infections caused by bacteria that are resistant to currently available materials. Since the expression of glycosidase enzymes within bacteria is unequally distributed, glycoside derivatives of antibacterial agents offer potential as targeted prodrugs for bacterial infections. Herein we report the synthesis and characterisation of four α-D-glycopyranosides and three β-D-glycopyranosides of the broad antibacterial agent triclosan, in generally good synthetic yields, and with excellent purities. Each glycoside was analysed to determine its ability to inhibit the growth of a wide range of Gram-negative and Gram-positive organisms, including many of clinical significance. All of the triclosan glycosides that were synthesized demonstrated antibacterial activity against many of the organisms that were examined. For example, β-galactoside (3a) and α-arabinoside (3c) had MIC values of 0.5 μg/ ml for several strains of S. aureus and S. haemolyticus. The triclosan glycosides were also generally found to be more water soluble and much more selective than the underivatized triclosan, making them ideal both for the targeted inhibition of bacterial growth and as agents for the selective recovery of bacteria from mixed cultures. In the latter case, two Bacillus strains could be identified from various strains of Bacillus and Staphylococcus after inoculation onto Nutri ent Agar No. 2 with 0.25 μg/ ml tri closan-α-D-glucopyranoside (3e). This glucoside may, therefore, be of use for the isolation and identification of the foodpoisoing organism Bacillus cereus

Generic theory of colloidal transport

We discuss the motion of colloidal particles relative to a two component fluid consisting of solvent and solute. Particle motion can result from (i) net body forces on the particle due to external fields such as gravity; (ii) slip velocities on the particle surface due to surface dissipative phenomena. The perturbations of the hydrodynamic flow field exhibits characteristic differences in cases (i) and (ii) which reflect different patterns of momentum flux corresponding to the existence of net forces, force dipoles or force quadrupoles. In the absence of external fields, gradients of concentration or pressure do not generate net forces on a colloidal particle. Such gradients can nevertheless induce relative motion between particle and fluid. We present a generic description of surface dissipative phenomena based on the linear response of surface fluxes driven by conjugate surface forces. In this framework we discuss different transport scenarios including self-propulsion via surface slip that is induced by active processes on the particle surface. We clarify the nature of force balances in such situations.Comment: 22 pages, 1 figur