Algorithm development

The past decade has seen considerable activity in algorithm development for the Navier-Stokes equations. This has resulted in a wide variety of useful new techniques. Some examples for the numerical solution of the Navier-Stokes equations are presented, divided into two parts. One is devoted to the incompressible Navier-Stokes equations, and the other to the compressible form

Kepler constraints on planets near hot Jupiters

We present the results of a search for planetary companions orbiting near hot Jupiter planet candidates (Jupiter-size candidates with orbital periods near 3 d) identified in the Kepler data through its sixth quarter of science operations. Special emphasis is given to companions between the 2∶1 interior and exterior mean-motion resonances. A photometric transit search excludes companions with sizes ranging from roughly two-thirds to five times the size of the Earth, depending upon the noise properties of the target star. A search for dynamically induced deviations from a constant period (transit timing variations) also shows no significant signals. In contrast, comparison studies of warm Jupiters (with slightly larger orbits) and hot Neptune-size candidates do exhibit signatures of additional companions with these same tests. These differences between hot Jupiters and other planetary systems denote a distinctly different formation or dynamical history

Legal Aspects of SIDS

My remarks today focus on four legal aspects of SIDS; the first three are problems of long standing and the fourth is less well recognized, an immediate problem to some but more of a cloud on the horizon to others. At the outset, I want to emphasize that I bring you no certain solutions. Rather my more modest objective is to provide a focus and framework for further discussions

Chemical Characterization and Source Apportionment of Household Fine Particulate Matter in Rural, Peri-urban, and Urban West Africa

Household air pollution in sub-Saharan Africa and other developing regions is an important cause of disease burden. Little is known about the chemical composition and sources of household air pollution in sub-Saharan Africa, and how they differ between rural and urban homes. We analyzed the chemical composition and sources of fine particles (PM2.5) in household cooking areas of multiple neighborhoods in Accra, Ghana, and in peri-urban (Banjul) and rural (Basse) areas in The Gambia. In Accra, biomass burning accounted for 39–62% of total PM2.5 mass in the cooking area in different neighborhoods; the absolute contributions were 10–45 μg/m3. Road dust and vehicle emissions comprised 12–33% of PM2.5 mass. Solid waste burning was also a significant contributor to household PM2.5 in a low-income neighborhood but not for those living in better-off areas. In Banjul and Basse, biomass burning was the single dominant source of cooking-area PM2.5, accounting for 74–87% of its total mass; the relative and absolute contributions of biomass smoke to PM2.5 mass were larger in households that used firewood than in those using charcoal, reaching as high as 463 μg/m3 in Basse homes that used firewood for cooking. Our findings demonstrate the need for policies that enhance access to cleaner fuels in both rural and urban areas, and for controlling traffic emissions in cities in sub-Saharan Africa

A Complexity Analysis of Smart Pixel Switching Nodes for Photonic Extended Generalized Shuffle Switching Networks

This paper studies the architectural tradeoffs found in the use of smart pixels for nodes within photonic switching interconnection networks are discussed. The particular networks of interest within the analysis are strictly nonblocking extended generalized shuffle (EGS) networks. Several performance metrics are defined for the analysis, and the effect of node size on these metrics is studied. Optimum node sizes are defined for each of the performance metrics and system-level limitations are identified

"The trauma of competition": the entry of Air Products Inc. into the industrial gases business in Britain and continental Europe 1947-1970

The British Oxygen Company (BOC) had a virtual monopoly on the supply of industrial gases (e.g. oxygen and acetylene) on the British market through the 1950s, when it was finally challenged by an American-based company, Air Products. Air Products Limited (APL) was able to undercut BOCs position, overcoming high barriers to entry to gain significant market share in this sector, which shares some features of network industries. Factors in this success included conditions imposed by the Board of Trade, APL’s innovations, BOC’s slow response, and favourable market conditions. APL’s success had implications for the internationalisation of the industrial gases industry