In Clear Creek, which runs through the Iowa State University campus in Ames, Iowa, USA, several types of iron mineralisation occur within stagnant pools and slow-moving water. This includes rusty flocs, commonly observed in mineral springs, rust-stained sediments and iridescent films (‘schwimmeisen’) on the pool surfaces. Observations of iron mineralisation over the course of more than a year in a single reach indicated that mineralisation occurred after precipitation events once water levels in the stream had dropped. Iron extracted and quantified from Clear Creek sediments and pool waters indicated the stream and its sediments were unlikely to be supplying the iron for mineralisation. We hypothesise that the observed mineralisation could result from the discharge of shallow, reducing groundwater-bearing Fe(II) into stagnant pools that form in debris-dammed areas of the stream. Piezometers installed next to the creek documented that shallow groundwater contained dissolved Fe, with the source of Fe being the floodplain sediments and the hydraulic gradient promoted groundwater discharge into the stream. Microorganisms identified in mineralised pools using 16S rRNA amplicon sequencing revealed an elevated presence of putative iron-oxidizing and iron-reducing microorganisms in mineralised vs. non-mineralised pools. Further investigation of the iridescent films revealed them to be composed of amorphous Fe(III) minerals. We further hypothesise that microbial exudates reduce surface tension and potential micro-zones for subsequent microbial iron redox cycling with dissolved organic matter in the pools. Determining the processes controlling mineralisation can lead to a better understanding of the ecological role of iron mineralisation in agricultural watersheds and the importance of contaminant degradation and nutrient cycling.

Small-angle X-ray scattering (SAXS) has been widely used as a microstructure characterization technology. In this work, a fully connected dense forward network is applied to inversely retrieve the mean particle size and particle distribution from SAXS data of samples dynamically compressed with high-power lasers and probed with X-ray free electron lasers. The trained network allows automatic acquisition of microstructure information, performing well in predictions on single-species nanoparticles on the theoretical model and in situ experimental data. We evaluate our network by comparing it with other methods, revealing its reliability and efficiency in dynamic experiments, which is of great value for in situ characterization of materials under high-power laser-driven dynamic compression.

Engineered products have economic, environmental, and social impacts, which comprise the major dimensions of sustainability. This paper seeks to explore interactions between design parameters when social impacts are incorporated into the concept development phase of the systems design process. Social impact evaluation is increasing in importance similar to what has happened in recent years with environmental impact consideration in the design of engineered products. Concurrently, research into new airship design has increased. Airships have yet to be reintroduced at a large scale or for a range of applications in society. Although airships have the potential for positive environmental and economic impacts, the social impacts are still rarely considered. This paper presents a case study of the hypothetical introduction of airships in the Amazon region of Brazil to help local farmers transport their produce to market. It explores the design space in terms of both engineering parameters and social impacts using a discrete-event simulation to model the system. The social impacts are found to be dependent not only on the social factors and airship design parameters but also on the farmer-airship system, suggesting that socio-technical systems design will benefit from integrated social impact metric analysis.

Engineered products have economic, environmental, and social impacts, which comprise the major dimensions of sustainability. This paper seeks to determine the interaction between design parameters when the social impacts are incorporated into the design process. Social impact evaluation is increasing in importance similar to what has happened with environmental impact consideration in recent years in the design of engineered products. Concurrently, research into new airship design has increased, however airships have yet to be reintroduced at a large scale and for a range of applications in society. Although airships have the potential for positive environmental and economic impacts, the social impacts are still rarely considered. This paper presents a case study of the hypothetical introduction of airships in the Amazon to help local farmers transport their produce to market. It explores the design space in terms of the airship's social impacts connected to the design parameters. The social impacts are found to be dependent not only on the social factors and airship design parameters, but also on the farmer-airship system, suggesting that socio-technical systems design will benefit from integrated social impact metric analysis.

Plate tectonics drives variation in sea-level, over intervals of approximately107–108 years. These variations may have significant effects on the pace of (biological) evolution through the elimination of terrestrial niches and the expansion of shallow-water marine niches. However, within the solar system, only the Earth experiences this kind of tectonism. Venus displays regional tectonism, characterized by rising diapirs within the plastic mantle. Impinging on the lithosphere, these plumes produce a range of structures of varying dimensions; the uplift of which would raise sea-level, were Venus to have oceans. Using Magellan observations of Venus, we model the impact of regional tectonism on sea-level for given areas of Venusian ocean, then compare the effect with terrestrial tectonic processes for similar oceanic area. We show that despite variation in the geographical extent of Venusian-style tectonic processes, the styles of regional tectonism on Venus can produce the same order of magnitude changes in sea-level, for a given area of ocean, as plate tectonics. Consequently, we examine some of the impacts of marine transgression on habitability and the evolution of life.

This paper explores dependencies between operational risks and between operational risks and other risks such as market, credit and insurance risk. The paper starts by setting the regulatory context and then goes into practical aspects of operational risk dependencies. Next, methods of modelling operational risk dependencies are considered with a simulation study exploring the sensitivity of diversification benefits arising from dependency models. The following two sections consider how correlation assumptions may be set, highlighting some generic dependencies between operational risks and with non-operational risks to assist in the assessment of dependencies and correlation assumptions. Supplementary appendices provide further detail on generic dependencies as well as a case study of how business models can lead to operational risks interacting with other risks. Finally, the paper finishes with a literature review of operational risk dependency papers including correlation studies and benchmark reports.

In September 2016, an imported case of measles in Edinburgh in a university student resulted in a further 17 confirmed cases during October and November 2016. All cases were genotype D8 and were associated with a virus strain most commonly seen in South East Asia. Twelve of the 18 cases were staff or students at a university in Edinburgh and 17 cases had incomplete or unknown measles mumps rubella (MMR) vaccination status. The public health response included mass follow-up of all identified contacts, widespread communications throughout universities in Edinburgh and prompt vaccination clinics at affected campuses. Imported cases of measles pose a significant risk to university student cohorts who may be undervaccinated, include a large number of international students and have a highly mobile population. Public health departments should work closely with universities to promote MMR uptake and put in place mass vaccination plans to prevent rapidly spreading measles outbreaks in higher educational settings in future.

Out-of-home foods (takeaway, take-out and fast foods) have become increasingly popular in recent decades and are thought to be a key driver in increasing levels of overweight and obesity due to their unfavourable nutritional content. Individual food choices and eating behaviours are influenced by many interrelated factors which affect the results of nutrition-related public health interventions. While the majority of research based on out-of-home foods comes from Australia, the UK and USA, the same issues (poor dietary habits and increased prevalence of non-communicable disease) are of equal concern for urban centres in developing economies undergoing ‘nutrition transition’ at a global scale. The present narrative review documents key facets, which may influence out-of-home food consumption, drawn from biological, societal, environmental, demographic and psychological spheres. Literature searches were performed and references from relevant papers were used to find supplementary studies. Findings suggest that the strongest determinants of out-of-home food availability are density of food outlets and deprivation within the built environment; however, the association between socio-economic status and out-of-home food consumption has been challenged. In addition, the biological and psychological drives combined with a culture where overweight and obesity are becoming the norm makes it ‘fashionable’ to consume out-of-home food. Other factors, including age group, ethnicity and gender demonstrate contrasting effects and a lack of consensus. It is concluded that further consideration of the determinants of out-of-home food consumption within specific populations is crucial to inform the development of targeted interventions to reduce the impact of out-of-home foods on public health.

As chemical management options for weeds become increasingly limited due to selection for herbicide resistance, investigation of additional nonchemical tools becomes necessary. Harvest weed seed control (HWSC) is a methodology of weed management that targets and destroys weed seeds that are otherwise dispersed by harvesters following threshing. It is not known whether problem weeds in western Canada retain their seeds in sufficient quantities until harvest at a height suitable for collection. A study was conducted at three sites over 2 yr to determine whether retention and height criteria were met by wild oat, false cleavers, and volunteer canola. Wild oat consistently shed seeds early, but seed retention was variable, averaging 56% at the time of wheat swathing, with continued losses until direct harvest of wheat and fababean. The majority of retained seeds were >45 cm above ground level, suitable for collection. Cleavers seed retention was highly variable by site-year, but generally greater than wild oat. The majority of seed was retained >15 cm above ground level and would be considered collectable. Canola seed typically had >95% retention, with the majority of seed retained >15 cm above ground level. The suitability ranking of the species for management with HWSC was canola>cleavers>wild oat. Efficacy of HWSC systems in western Canada will depend on the target species and site- and year-specific environmental conditions.

Limitations of access have long restricted exploration and investigation of the cavities beneath ice shelves to a small number of drillholes. Studies of sea-ice underwater morphology are limited largely to scientific utilization of submarines. Remotely operated vehicles, tethered to a mother ship by umbilical cable, have been deployed to investigate tidewater-glacier and ice-shelf margins, but their range is often restricted. The development of free-flying autonomous underwater vehicles (AUVs) with ranges of tens to hundreds of kilometres enables extensive missions to take place beneath sea ice and floating ice shelves. Autosub2 is a 3600 kg, 6.7 m long AUV, with a 1600 m operating depth and range of 400 km, based on the earlier Autosub1 which had a 500 m depth limit. A single direct-drive d.c. motor and five-bladed propeller produce speeds of 1–2 m s−1. Rear-mounted rudder and stern-plane control yaw, pitch and depth. The vehicle has three sections. The front and rear sections are free-flooding, built around aluminium extrusion space-frames covered with glass-fibre reinforced plastic panels. The central section has a set of carbon-fibre reinforced plastic pressure vessels. Four tubes contain batteries powering the vehicle. The other three house vehicle-control systems and sensors. The rear section houses subsystems for navigation, control actuation and propulsion and scientific sensors (e.g. digital camera, upward-looking 300 kHz acoustic Doppler current profiler, 200 kHz multibeam receiver). The front section contains forward-looking collision sensor, emergency abort, the homing systems, Argos satellite data and location transmitters and flashing lights for relocation as well as science sensors (e.g. twin conductivity–temperature–depth instruments, multibeam transmitter, sub-bottom profiler, AquaLab water sampler). Payload restrictions mean that a subset of scientific instruments is actually in place on any given dive. The scientific instruments carried on Autosub are described and examples of observational data collected from each sensor in Arctic or Antarctic waters are given (e.g. of roughness at the underside of floating ice shelves and sea ice).

The development of an economic capital model requires a decision to be made regarding how to aggregate capital requirements for the individual risk factors while taking into account the effects of diversification. Under the Individual Capital Adequacy Standards framework, UK life insurers have commonly adopted a correlation matrix approach due to its simplicity and ease in communication to the stakeholders involved, adjusting the result, where appropriate, to allow for non-linear interactions. The regulatory requirements of Solvency II have been one of the principal drivers leading to an increased use of more sophisticated aggregation techniques in economic capital models. This paper focusses on a simulation-based approach to the aggregation of capital requirements using copulas and proxy models. It describes the practical challenges in parameterising a copula including how allowance may be made for tail dependence. It also covers the challenges associated with fitting and validating a proxy model. In particular, the paper outlines how insurers could test, communicate and justify the choices made through the use of some examples.