Divorce Rates Better Predict Population-Level Reproductive Success in Little Penguins Than Foraging Behaviour or Environmental Factors.

Understanding the relative contributions of environmental, behavioural and social factors to reproductive success is crucial for predicting population dynamics of seabirds. However, these factors are often studied in isolation, limiting our ability to evaluate their combined influence. This study investigates how marine environmental variables, foraging behaviour and social factors (divorce), influence reproductive success in little penguins () over 13 breeding seasons.

Gas transport across the low-permeability containment zone of an underground nuclear explosion.

Understanding the nature of gas transport from an underground nuclear explosion (UNE) is required for evaluating the ability to detect and interpret either on-site or atmospheric signatures of noble gas radionuclides resulting from the event. We performed a pressure and chemical tracer monitoring experiment at the site of an underground nuclear test that occurred in a tunnel in Nevada to evaluate the possible modes of gas transport to the surface. The site represents a very well-contained, low gas-permeability end member for past UNEs at the Nevada National Security Site.

The characteristic release of noble gases from an underground nuclear explosion.

Prompt release of gases at the ground surface resulting from explosively propagated vents or large operational releases has typically been considered to be the only mode of transport for detonation gases from an underground nuclear explosion (UNE) giving rise to detectable levels of radioxenon gases in downwind atmospheric samples captured at distances exceeding 100 km. Using a model for thermally and barometrically driven post-detonation transport across the broad surface of a simulated UNE site, we show in conjunction with the results of an atmospheric tracer-release experiment that even deep, well-contained UNEs, without prompt vents or leaks, are potentially detectable tens of kilometers downwind with current technology; distances that are significant for localizing the source of detected atmospheric signals during on-site monitoring or inspection. For a given yield, the bulk permeability of the UNE site and to a lesser extent the depth of detonation appear to be the primary source-term parameters controlling the distance of detection from the detonation point.

International challenge to model the long-range transport of radioxenon released from medical isotope production to six Comprehensive Nuclear-Test-Ban Treaty monitoring stations.

After performing a first multi-model exercise in 2015 a comprehensive and technically more demanding atmospheric transport modelling challenge was organized in 2016. Release data were provided by the Australian Nuclear Science and Technology Organization radiopharmaceutical facility in Sydney (Australia) for a one month period. Measured samples for the same time frame were gathered from six International Monitoring System stations in the Southern Hemisphere with distances to the source ranging between 680 (Melbourne) and about 17,000 km (Tristan da Cunha).