Long-term evolution of highly alkaline steel slag drainage waters

© 2015, Springer International Publishing Switzerland. The disposal of slag generated by the steel industry can have negative consequences upon the surrounding aquatic environment by the generation of high pH waters, leaching of potentially problematic trace metals, and rapid rates of calcite precipitation which smother benthic habitats. A 36-year dataset was collated from the long-term ambient monitoring of physicochemical parameters and elemental concentrations of samples from two steel slag leachate-affected watercourses in northern England. Waters were typified by elevated pH ( > 10), high alkalinity, and were rich in dissolved metals (e.g. calcium (Ca), aluminium (Al), and zinc (Zn)). Long-term trend analysis was performed upon pH, alkalinity, and Ca concentration which, in addition to Ca flux calculations, were used to highlight the longevity of pollution arising as a result of the dumping and subsequent leaching of steel slags. Declines in calcium and alkalinity have been modest over the monitoring period and not accompanied by significant declines in water pH. If the monotonic trends of decline in alkalinity and calcium continue in the largest of the receiving streams, it will be in the region of 50–80 years before calcite precipitation would be expected to be close to baseline levels, where ecological impacts would be negligible

The potential use of exhausted open pit mine voids as sinks for atmospheric CO2: insights from natural reedbeds and mine water treatment wetlands

Abandoned surface mine voids are often left to flood, forming pit lakes. Drawing simple but important lessons from experiences with compost-based passive remediation systems for acidic mine waters, an alternative end-use for open pit mine voids is proposed: gradual infilling with organic material, which can serve as a long-term sink for atmospheric CO2, whilst ameliorating or eventually eliminating sustained evaporative water loss and acidic water pollution. Key to the success of this approach is the suppression of methane release from organic sediments flooded with sulfate-rich mine waters: the presence of modest amounts of sulfate (which is typically abundant in mine waters) inhibits the activity of methanogenic bacteria. This explains why gas release studies of mine water treatment wetlands never report methane emissions; CO2 is the only greenhouse gas emitted, and this is clearly not at levels sufficient to undo the benefits of wetlands as net CO2 sinks. While the compete infilling of open pits with organic sediments might take a very long time, only minimal maintenance would be needed, and if carbon trading markets finally mature, a steady income stream could be obtained to cover the costs, thus extending the economic life of the mine site far beyond cessation of mining

Understanding Addiction as a Developmental Disorder: An Argument for a Developmentally Informed Multilevel Approach

Substance abuse and drug addiction are two of the most common psychopathologies among the general population. While a host of risk factors are associated with the onset of drug abuse and drug addiction, there is a growing body of evidence pointing to the powerful influence of early adverse experiences, both child neglect and maltreatment, as well as drug use and abuse in parents and/or primary caretakers. We consider the case for drug addiction as a developmental disorder, outlining the need to consider the role of genetic, epigenetic, and neurobiological factors alongside experiences of adversity at key stages of development. Such a multilevel approach within a developmental framework has the potential to reframe our understanding of how addiction emerges and is maintained, and is essential if we are to identify the mechanisms underlying this disorder to better inform effective treatment and prevention across the generations

The quality of monetary policy and inflation performance: globalization and its aftermath

With a few unfortunate exceptions the last three decades have seen reductions in inflation around the world to the point that many would argue that further improvements in price stability would offer only limited welfare gains. This experience is the result of many factors, some of which are country-specific. In this paper we seek to isolate one of the factors, namely, the improvement in the quality of monetary policy. There are two novel aspects to the study. Firstly, we essentially estimate a gravity-like model. Secondly, we propose generally a more exhaustive analysis of the potential role of a large number of institutional factors than has been done before. Briefly, we find that institutional factors play a role in explaining inflation relative to the US experience, which is used as the benchmark. Nevertheless, any reduction in inflation stemming from greater central bank autonomy is a feature of the 1980s and early 1990s. Thereafter, central banks in the OECD look very much alike.globalization; inflation differentials; monetary policy strategy; institutional change

Preanthesis biomass accumulation of plant and plant organs defines yield components in wheat

The preanthesis period in wheat is critical for growth of plant organs including leaves, stems, spikes and roots. However, the roles of the preanthesis biomass accumulation of plant and plant organs in yield determination are only partially elucidated, and the underlying genetic basis remains largely unknown. This study aimed to understand the physiological and genetic relationships between preanthesis biomass accumulation and yield determination. In a mapping population of bread wheat (Triticum aestivum ‘Forno’) and its relative spelt (Triticum spelta ‘Oberkulmer’) contrasting for biomass, the dry weight of above-ground whole shoots and different organs, and leaf area, were analysed at GS39 (full flag leaf emergence) and anthesis. Yield components (thousand grain weight, grains per spike, final shoot biomass and grain weight per spike) and plant height were measured at maturity, followed by identification of quantitative trait loci (QTL) for all above traits. Field experiments were carried out in UK in 2011–2012 and 2012–2013 seasons, each using a randomised complete block design with three replicates. The results showed that there was a significant variation in biomass and its partitioning to organs at different stages. Consistent with the previous findings, stem water soluble carbohydrates and spike dry weight at anthesis contributed to thousand grain weight and grains per spike, respectively. In addition, this study revealed many other traits positively associated with one or more yield components, including biomass and leaf area at GS39, leaf and structural stem growth as well as whole shoot biomass at anthesis, and higher dry matter accumulation and crop (and spike) growth rates between the two stages. Increasing shoot biomass by removing other tillers at GS39 led to higher grain number and grain weight per spike. These results indicate the importance of the preanthesis growth of plant and plant organs for yield determination. Plant height was only weakly correlated with final biomass at maturity so it is possible to produce high-biomass genotypes without increasing plant height. Genetic analysis revealed 193 QTL associated with biomass and biomass-related traits. Frequent QTL coincidences between biomass and yield traits were observed, mainly on chromosomes 2B, 3A, 4A, 4B, 5A, 6A and 7B, indicating pleiotropy or tight gene linkages, consistent with their phenotypic associations. The preanthesis biomass traits associated with yield components and the underlying QTL, would facilitate the trait-based physiological and molecular breeding in wheat

Recent Advances to Estimation of Fixed-Interface Modal Models Using Dynamic Substructuring

In 2010, Allen & Mayes proposed to estimate the fixed-interface modes of a structure by measuring the modes of the structure bolted to a fixture and then applying constraints to the fixture using the transmission simulator method. While the method proved useful, and has indeed been used in studies since that point, a few peculiarities were noted. First, in some cases the estimated fixed-base natural frequencies were observed to converge very slowly to the true values (in simulated experiments) as the number of constraints was increased. To formulate these constraints, prior studies used only the free-interface modes of the fixture or the measured modes of the assembly. This work extends that to consider other sets of constraints, showing improved results. Furthermore, in some prior studies it has been observed that there were errors of more than 10% in the natural frequencies even when the fixture motion was hundreds of times smaller than the motion of the structure of interest (and so it had presumably been removed). This work explores this phenomenon, seeking to use the strain energy in the fixture, to the extent that it can be estimated using a test-analysis model for the fixture, as a metric to predict frequency error. The proposed methods are explored by applying them to simulated measurements from a beam and from the NASA Space Launch System coupled to the Mobile Launcher

Can aggregate quarry silt lagoons provide resources for wading birds?

Wading birds have declined across Europe as the intensification of lowland agriculture has resulted in the loss and degradation of wetland areas. Lowland aggregate extraction sites that incorporate areas of fine, waste sediments deposited in silt lagoons have the potential to be restored for wader conservation. We set out to determine the potential value of silt lagoons to wading birds by comparing the water quality, sediment profiles, aquatic invertebrate abundance and diversity (prey availability) and wader site use at five sites representing various stages of active aggregate extraction and restoration for conservation purposes. Wader counts were conducted monthly over a twelve month period using replicated scan samples, and the invertebrate communities studied during the breeding and autumn migration season (June–September). Water quality variables were similar between sites, but sediments from active quarries were dominated by moderately sorted fine sands in comparison to the coarser sediment profiles of restored areas. June and September there was no significant difference in invertebrate diversity between sites, however richness was significantly lower on quarry sites and total abundance a factor of ten higher at restored sites than on silt lagoons, with the dominant taxa similar across all sites. Waders used all sites; albeit at lower abundance and richness on silt lagoons and two species were recorded breeding on active silting sites. We conclude that the fine, uniform sediments of modern silt lagoons limited invertebrate diversity and abundance, diminishing the value of silt lagoons to waders. Simple low-cost intervention measures increasing substrate heterogeneity and creating temporary ponds could increase invertebrate richness and abundance, and enhance the conservation potential of these sites

Identifying seedling root architectural traits associated with yield and yield components in wheat

Background and Aims: Plant roots growing underground are critical for soil resource acquisition, anchorage and plant-environment interactions. In wheat (Triticum aestivum), however, the target root traits to improve yield potential still remain largely unknown. This study aimed to identify traits of seedling root system architecture (RSA) associated with yield and yield components in 226 recombinant inbred lines (RILs) derived from a cross between the bread wheat Triticum aestivum ‘Forno’ (small, wide root system) and spelt Triticum spelta ‘Oberkulmer’ (large, narrow root system). Methods: A ‘pouch and wick’ high-throughput phenotyping pipeline was used to determine the RSA traits of 13-d-old RIL seedlings. Two field and one glasshouse experiments were carried out to investigate the yield, yield components and phenology, followed by identification of quantitative trait loci (QTL). Key Results: There was substantial variation in RSA traits between genotypes. Seminal root number and total root length were both positively associated with grains m-2, grains per spike, above-ground biomass m-2, and grain yield. More seminal roots and longer total root length were also associated with delayed maturity and extended grain filling, likely to be a consequence of more grains being defined before anthesis. Additionally, the maximum width of the root system displayed positive relationships with spikes m-2, grains m-2, and grain yield. Ten RILs selected for longest total roots exhibited the same effects on yield and phenology as described above, compared to the ten lines with shortest total roots. Genetic analysis revealed 38 QTL for the RSA, and QTL coincidence between the root and yield traits were frequently observed, indicating tightly linked genes or pleiotropy, which concurs with the results of phenotypic correlation analysis. Conclusions: Based on the results from the Forno × Oberkulmer population, it is proposed that vigorous early root growth, particularly more seminal roots and longer total root length, is important to improve yield potential, and should be incorporated into wheat ideotypes in breeding