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A convergence theory for the hp -FEM applied to a variety of constant-coefficient Helmholtz problems was pioneered in the papers [35] , [36] , [15] , [34]. This theory shows that, if the solution operator is bounded polynomially in the wavenumber k , then the Galerkin method is quasioptimal provided that h k / p ≤ C 1 and p ≥ C 2 log ⁡ k , where C 1 is sufficiently small, C 2 is sufficiently large, and both are independent of k , h , and p. The significance of this result is that if h k / p = C 1 and p = C 2 log ⁡ k , then quasioptimality is achieved with the total number of degrees of freedom proportional to k d ; i.e., the hp -FEM does not suffer from the pollution effect. This paper proves the analogous quasioptimality result for the heterogeneous (i.e. variable-coefficient) Helmholtz equation, posed in R d , d = 2 , 3 , with the Sommerfeld radiation condition at infinity, and C ∞ coefficients. We also prove a bound on the relative error of the Galerkin solution in the particular case of the plane-wave scattering problem. These are the first ever results on the wavenumber-explicit convergence of the hp -FEM for the Helmholtz equation with variable coefficients. [ABSTRACT FROM AUTHOR]

Between 1972 (Stockholm) and 1996 (Rimouski), global awareness in relation to coastal management moved from a sectoral to a comprehensiveand integrated approach, from the protection of the marine environment and coastal resources to the concept of sustainable development. This paper summarizes the progress made at the international level in relation to coastal management issues, with particular emphasis to the post-UNCED Rio Declaration. A synthesis of the main highlights and outcomes of the Coastal Zone Canada '96 International Conference (CZC'96) held at Rimouski, Canada, is then presented. Two declarations ofprinciple (The Rimouski Declaration and Call for International Action) were adopted by the participants at CZC'96. They call for Canada and other international governments to better define national objectives, programs, and mechanisms permitting coastal communities to play afull and active role in the intelligent and practical management of coastal and maritime resources, and to meet their international coastal and ocean obligations thereby contributing to the sustainability of the oceans. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is a leading cause of intramammary infections (IMI). We recently demonstrated that Staph. aureus strains express the gene guaA during bovine IMI. This gene codes for a guanosine monophosphate synthetase and its expression is regulated by a guanine riboswitch. The guanine analog 2,5,6-triaminopyrimidine-4-one (PC1) is a ligand of the guanine riboswitch. Interactions between PC1 and its target result in inhibition of guanosine monophosphate synthesis and subsequent death of the bacterium. The present study describes the investigational use of PC1 for therapy of Staph. aureus IMI in lactating cows. The in vitro minimal inhibitory concentration of PC1 ranged from 0.5 to 4 µg/mL for a variety of Staph. aureus and Staphylococcus epidermidis strains and required a reducing agent for stability and full potency. A safety assessment study was performed, whereby the healthy quarters of 4 cows were infused with increasing doses of PC1 (0, 150, 250, and 500 mg). Over the 44 h following infusions, no obvious adverse effect was observed. Ten Holstein multiparous cows in mid lactation were then experimentally infused into 3 of the quarters with approximately 50 cfu of Staph. aureus strain SHY97-3906 and infection was allowed to progress for 2 wk before starting PC1 treatment. Bacterial counts reached then about 10³ to 104 cfu/mL of milk. Infected quarters were treated with 1 of 3 doses of PC1 (0, 250, or 500 mg) after each morning and evening milking for 7 d (i.e., 14 intramammary infusions of PC1). During the treatment period, milk from PC1-treated quarters showed a significant reduction in bacterial concentrations. However, this reduction of Staph. aureus count in milk was not maintained during the 4 wk following the end of the treatment and only 15% of the PC1-treated quarters underwent bacteriological cure. The somatic cell count and the quarter milk production were not affected by treatments. Although bacterial clearance was not achieved following treatment with PC1, these results demonstrate that the Staph. aureus guanine riboswitch represents a relevant and promising drug target for a novel class of antibiotics for the animal food industry. [ABSTRACT FROM AUTHOR]