We consider accretion discs in close binary systems. We show that heating of a disc at the impact point of the accretion stream contributes significantly to the local energy budget at its outer edge. As a result the thermal balance relation between local accretion rate and surface density (the ‘S–curve’) changes; the critical mass transfer rate above which no dwarf nova outbursts occur can be u...

We have built a highly sensitive torsion balance to investigate small forces between closely spaced gold coated surfaces. Such forces will occur between the LISA proof mass and its housing. These forces are not well understood and experimental investigations are imperative. We describe our torsion balance and present the noise of the system. A significant contribution to the LISA noise budget a...

An honest declaration of the error in a mass, momentum or energy balance, ε, simply raises the question of its acceptability: “At what value of ε is the attempted balance to be rejected?” Answering this question requires a reference quantity against which to compare ε. This quantity must be a mathematical function of all the data used in making the balance. To deliver this function, a theory gr...

BACKGROUND The use of cost-effectiveness thresholds based on a country's income per capita has been criticized for not being relevant to decision making, in particular in middle-income countries such as South Africa. The recent South African HIV Investment Case produced an alternative cost-effectiveness threshold for HIV prevention and treatment interventions based on estimates of life years sa...

We examine the most recent observational constraints arising from i) small-scale and large-scale Galactic dynamical properties, ii) star counts of population I and II stars at faint magnitude and iii) microlensing experiments towards the Large Magellanic Cloud and the Galactic centre. From these constraints, we determine the halo and disk stellar mass functions and stellar content down to the b...

The atmospheric budget of methyl bromide (CH(3)Br), an ozone-depleting gas, is highly uncertain, because it has complex sources and sinks. Although oceans, biomass burning, and industrial production are identified as the major sources, the fraction of CH(3)Br that is contributed by each source is not well known. A mass-balance approach that exploits differences in the carbon isotopic signature ...