258 research outputs found
The ergonomics of command and control
Since its inception, just after the Second World War, ergonomics research has paid special attention to the issues surrounding human control of systems. Command and Control environments continue to represent a challenging domain for Ergonomics research. We take a broad view of Command and Control research, to include C2 (Command and Control), C3 (Command, Control and Communication), and C4 (Command, Control, Communication and Computers) as well as human supervisory control paradigms. This special issue of ERGONOMICS aims to present state-of-the-art research into models of team performance, evaluation of novel interaction technologies, case studies, methodologies and theoretical review papers. We are pleased to present papers that detail research on these topics in domains as diverse as the emergency services (e.g., police, fire, and ambulance), civilian applications (e.g., air traffic control, rail networks, and nuclear power) and military applications (e.g., land, sea and air) of command and control. While the domains of application are very diverse, many of the challenges they face share interesting similarities
Opening Our Eyes : How film contributes to the culture of the UK
Opening our eyes looks at how films are consumed and the factors which affect people’s viewing choices. It also covers the relationships audiences report between film and other activities. It goes on to explore the sorts of effects which film has upon people, their sense of identity and relationship with the world. Finally it looks at the various effects which individual films have had on those surveyed and reaches a number of conclusions.Final Published versio
Assessing the clogging and permeability of degrading packed bed reactors
In South Africa, the need for water treatment is increasing, especially in the mining sector. As active water treatment technologies are expensive, the mining sector has an increasing need for passive water treatment technology, with low maintenance and operating costs, yet efficient water treatment ability. Literature on passive water treatment suggests that these systems only offer a narrow range of treatment capabilities. Therefore, hybrid water treatment systems could be a solution to low-cost water treatment in South Africa. The degrading packed bed reactor (DPBR) is one of the units comprising the hybrid treatment group. The DPBR’s main action is to convert sulfates into sulfides and alkalinity, since this reduces the impact on the environment by increasing the pH and reducing the salinity. In this study, 6 small-scale DPBRs were constructed. Each was classified according to its unique organic source (manure, straw, vegetable food processing waste, wood shavings, chicken litter and a combined sample with layers of all the carbon sources). Synthetic acid mine drainage (AMD) was fed through the 6 bioreactors for a period of 3 months. Permeabilities, leachate samples and effective void volumes were measured from the DPBRs. From the experiments conducted, it was found that the manure and combination bioreactors (with equal layers of manure, straw, compost, wood shavings and chicken litter) had the lowest overall permeabilities, with straw and compost having the highest permeabilities. Linked to this, the experiments showed that the manure and combination bioreactors had the largest decreases in effective porosity with straw and compost having the least. Hydraulically, the combination bioreactor performed the best by incorporating the best attributes from each carbon source. Wood shavings preformed almost as well. Chicken litter clogged within 18 days after the initiation of the experiment and thus was the least effective substrate.Keywords: degrading packed bed reactor, cloggin
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Plant and amphibian assemblages in zero-order basins in the Oregon Coast Range
We have a poor understanding of the biotic communities in zero-order basins, drainages extending from ridgelines to the initiation of first-order streams. This study describes baseline plant and amphibian composition in unmanaged zero-order basins in the Oregon Coast Range. Specifically, I studied: i) the spatial distribution and diversity of species, including riparian-associates; and ii) the dominant environmental, spatial and geomorphic gradients in species composition The results of this research have implications for riparian management in steep, forested landscapes in the Pacific Northwest. The composition of tree and shrub layers in zero-order basins was more similar to upland areas than to larger-order riparian areas. Douglas-fir, western hemlock, and western red cedar had highest basal areas; bigleaf maple had highest hardwood density. Convergent areas (areas collecting surface flow) had significantly lower relative densities than surrounding slopes. I identified 138 forest floor herb, shrub, and seedling tree species in zero-order basins. Gradient analysis and empirical modeling suggested that the composition of forest floor plant assemblages was associated with environmental parameters related to geomorphic position and overstory characteristics, such as distance from basin center, basin aspect and overstory relative density. Vegetation types, developed using classification, followed similar environmental patterns. Vegetation types were useful in clarifying environmental gradients acting on groups of plant species, and in delineating the lateral extent of geomorphic and fluvial influences. Riparian-associated vegetation types were mostly restricted to valley floors and lower slope areas. Geomorphic and lateral surfaces were drivers of environmental gradients in zero-order basins; plant species composition followed these geomorphic gradients. Surfaces close to basin center ("inner gorges"), including valley centers, splash zones, and lower slope areas, supported the highest plant species diversity and most distinct plant assemblages. The spatial distribution patterns of amphibian species and assemblages were characterized along longitudinal and lateral gradients, and relative to three geomorphic surfaces (valleys, headmost areas and slopes), and empirical species-habitat models were developed. I identified eight amphibian species in zero-order basins (865 total captures), and analyzed data for six. Headmost areas supported a distinctive upland amphibian assemblage, while valley floors had the highest riparian amphibian diversity. Captures of three riparian species were higher in valley surfaces, within S m of the center of zero-order basins, while captures of three upland species were highest in areas 2-5 m from center. Upland-associated species were captured two times farther from basin centers than riparian-associated species. The best predictors of amphibian captures in empirical models were geomorphic, stability/ disturbance, moisture and overstory parameters. Ordination and indicator species analysis facilitated characterization of amphibian species assemblages within geomorphic surface zones, and suggested spatial compression of habitats and species in zero-order basins, in comparison to broader spatial extents in larger basins. Plant and amphibian assemblages in unmanaged zero-order basins were most similar to each other in their lateral and geomorphic spatial patterning, including the importance of inner gorge areas for support of diverse communities. Plant species were strongly associated with geomorphic position parameters, while amphibians had stronger ties to discrete microhabitat elements such as moisture levels and large substrate. Amphibians appeared to have a more distinctive assemblage in headmost areas than plant species. Results suggest that assemblages of plants and amphibians in these basins are distinct from both larger-order riparian assemblages and from vegetation in surrounding hillslopes. Riparian management designs could take these spatial patterns and habitat associations into account to maintain the ecological integrity of headwater communities. The longitudinal and lateral extents of landscape areas managed to minimize risk to persistence of zero-order basin plant and amphibian assemblages would need to incorporate both fluvial and hillslope disturbance regimes, and microhabitat features associated with them
Computational Analysis of Mouse piRNA Sequence and Biogenesis
The recent discovery of a new class of 30-nucleotide long RNAs in mammalian testes, called PIWI-interacting RNA (piRNA), with similarities to microRNAs and repeat-associated small interfering RNAs (rasiRNAs), has raised puzzling questions regarding their biogenesis and function. We report a comparative analysis of currently available piRNA sequence data from the pachytene stage of mouse spermatogenesis that sheds light on their sequence diversity and mechanism of biogenesis. We conclude that (i) there are at least four times as many piRNAs in mouse testes than currently known; (ii) piRNAs, which originate from long precursor transcripts, are generated by quasi-random enzymatic processing that is guided by a weak sequence signature at the piRNA 5′ends resulting in a large number of distinct sequences; and (iii) many of the piRNA clusters contain inverted repeats segments capable of forming double-strand RNA fold-back segments that may initiate piRNA processing analogous to transposon silencing
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