2,957 research outputs found

    Food Apocalypse Now: An Epistemological Understanding of the Coming Food Crisis

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    Proactivity Toward Workplace Safety Improvement: An Investigation of Its Motivational Drivers and Organizational Outcomes

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    Initiating a safety oriented change - or safety initiative - is conceptually distinct from other forms of safety participation and safety citizenship behaviour, yet little attention has been given to its performance outcomes or its motivational antecedents. An initial study with a sample composed of middle managers (N = 86) showed that safety initiative predicted objective improvement actions six months later, whereas, showing differential validity, safety compliance predicted the implementation of monitoring actions. Two subsequent studies focused on motivational antecedents. First, using a sample of team leaders (N = 295), we tested a higher-order structure of proactive motivation that incorporates three domains: “can do”, “reason to” and future orientation. Second, in a longitudinal study of chemical work operators (N = 188), after checking for the influence of potential confounds (past behaviours; accidents experience; perceived risk), we showed that safety initiative was predicted only by proactive motivation. Instead, safety compliance was found to be associated with affective commitment and scrupulousness, whereas safety helping was found to be associated with affective commitment. Self-reported behaviours were validated against rater assessments. This study supports the importance of distinguishing safety initiative from other safety behaviours, indicating how to create an organizational context supporting a proactive management of workplace safety

    Spatiotemporal characterisation of Fire Severity Over a 23 Year Period in South-East Queensland using data collected with Landsat sensors: A preliminary study

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    Land management agencies are increasingly using multispectral satellite imagery to monitor post-fire ground conditions to guide effective conservation and asset protection management strategies. Estimates derived from such data can span over multiple decades and can be analysed to identify spatiotemporal burnt area patterns. Interestingly, fire severity is rarely derived from multi-decadal remote sensing datasets. Accordingly, in this study we explored the utility of imagery captured with Landsat sensors (5 TM, 7 ETM+ and 8 OLI) to characterise fire severity of burnt areas over a 23 year period in a national park with a woodland and heath ecosystem. The multi-temporal differenced normalised burn ratio (dNBR) was used to estimate fire severity for individual burnt areas, which were then aggregated to identify spatiotemporal patterns. Accuracy assessment was achieved using ground truth data collected with the Geometrically Structured Composite Burn Index (GeoCBI), which incorporates the fraction of cover (FCOV) of vegetation over the total plot. Our results indicated that Landsat imagery was ideal for significantly estimating fire severity (accuracy = 72 %, kappa = 0.63, P = < 0.001) in sclerophyll woodland and heath ecosystems. Further, we had interesting insight into the patterns of increased fire severity within specific vegetation types and across the study site

    Beyond motivation: Job and work design for development, health, ambidexterity, and more

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    Much research shows it is possible to design motivating work, which has positive consequences for individuals and their organizations. This article reviews research that adopts this motivational perspective on work design, and it emphasizes that it is important to continue to refine motivational theories. In light of continued large numbers of poor-quality jobs, attention must also be given to influencing practice and policy to promote the effective implementation of enriched work designs. Nevertheless, current and future work-based challenges mean that designing work for motivation is necessary but insufficient. This review argues that work design can be a powerful vehicle for learning and development, for maintaining and enhancing employees' physical and mental health, and for achieving control and flexibility simultaneously (for example, in the form of ambidexterity); all these outcomes are important given the challenges in today's workplaces. The review concludes by suggesting methodological directions

    Impacts of climate variability and future climate change on harmful algal blooms and human health

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.Anthropogenically-derived increases in atmospheric greenhouse gas concentrations have been implicated in recent climate change, and are projected to substantially impact the climate on a global scale in the future. For marine and freshwater systems, increasing concentrations of greenhouse gases are expected to increase surface temperatures, lower pH, and cause changes to vertical mixing, upwelling, precipitation, and evaporation patterns. The potential consequences of these changes for harmful algal blooms (HABs) have received relatively little attention and are not well understood. Given the apparent increase in HABs around the world and the potential for greater problems as a result of climate change and ocean acidification, substantial research is needed to evaluate the direct and indirect associations between HABs, climate change, ocean acidification, and human health. This research will require a multidisciplinary approach utilizing expertise in climatology, oceanography, biology, epidemiology, and other disciplines. We review the interactions between selected patterns of large-scale climate variability and climate change, oceanic conditions, and harmful algae.This work was funded in part through grants from the NSF/NIEHS Centers for Oceans and Human Health, grant numbers NSF OCE04-32479 and NIEHS P50 ES012740 (EAL), NSF OCE-0432368 and NIEHS P50 ES012736 (LEF), NIEHS P50 ES012762 and NSF OCE-0434087 (SKM, MSP). SKM, VLT and NJM also were supported in part by the West Coast Center for Oceans and Human Health (WCCOHH) as part of the NOAA Oceans and Human Health Initiative, and this is WCCOHH publication no. 26. The WCCOHH is part of the National Marine Fisheries Service's Northwest Fisheries Science Center, Seattle, Washington

    Assessing population impacts of toxicant-induced disruption of breeding behaviours using an individual-based model for the three-spined stickleback

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     This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThe effects of toxicant exposure on individuals captured in standard environmental risk assessments (ERA) do not necessarily translate proportionally into effects at the population-level. Population models can incorporate population resilience, physiological susceptibility, and likelihood of exposure, and can therefore be employed to extrapolate from individual- to population-level effects in ERA. Here, we present the development of an individual-based model (IBM) for the three-spined stickleback (Gasterosteus aculeatus) and its application in assessing population-level effects of disrupted male breeding behaviour after exposure to the anti-androgenic pesticide, fenitrothion. The stickleback is abundant in marine, brackish, and freshwater systems throughout Europe and their complex breeding strategy makes wild populations potentially vulnerable to the effects of endocrine disrupting chemicals (EDCs). Modelled population dynamics matched those of a UK field population and the IBM is therefore considered to be representative of a natural population. Literature derived dose-response relationships of fenitrothion-induced disruption of male breeding behaviours were applied in the IBM to assess population-level impacts. The modelled population was exposed to fenitrothion under both continuous (worst-case) and intermittent (realistic) exposure patterns and population recovery was assessed. The results suggest that disruption of male breeding behaviours at the individual-level cause impacts on population abundance under both fenitrothion exposure regimes; however, density-dependent processes can compensate for some of these effects, particularly for an intermittent exposure scenario. Our findings further demonstrate the importance of understanding life-history traits, including reproductive strategies and behaviours, and their density-dependence, when assessing the potential population-level risks of EDCs.Syngenta LtdBiotechnology and Biological Sciences Research Council (BBSRC

    Some Curvature Problems in Semi-Riemannian Geometry

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    In this survey article we review several results on the curvature of semi-Riemannian metrics which are motivated by the positive mass theorem. The main themes are estimates of the Riemann tensor of an asymptotically flat manifold and the construction of Lorentzian metrics which satisfy the dominant energy condition.Comment: 25 pages, LaTeX, 4 figure

    Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption

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    Explosive energy release is a common phenomenon occurring in magnetized plasma systems ranging from laboratories, Earth's magnetosphere, the solar corona and astrophysical environments. Its physical explanation is usually attributed to magnetic reconnection in a thin current sheet. Here we report the important role of magnetic flux rope structure, a volumetric current channel, in producing explosive events. The flux rope is observed as a hot channel prior to and during a solar eruption from the Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamic Observatory (SDO). It initially appears as a twisted and writhed sigmoidal structure with a temperature as high as 10 MK and then transforms toward a semi-circular shape during a slow rise phase, which is followed by fast acceleration and onset of a flare. The observations suggest that the instability of the magnetic flux rope trigger the eruption, thus making a major addition to the traditional magnetic-reconnection paradigm.Comment: 13 pages, 3 figure

    Investigation of MoOx/Al2O3 under Cyclic Operation for Oxidative and Non-Oxidative Dehydrogenation of Propane

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    A MoOx/Al2O3 catalyst was synthesised and tested for oxidative (ODP) and non-oxidative (DP) dehydrogenation of propane in a reaction cycle of ODP followed by DP and a second ODP run. Characterisation results show that the fresh catalyst contains highly dispersed Mo oxide species in the +6 oxidation state with tetrahedral coordination as [MoVIO4]2− moieties. In situ X-ray Absorption Spectroscopy (XAS) shows that [MoVIO4]2− is present during the first ODP run of the reaction cycle and is reduced to MoIVO2 in the following DP run. The reduced species are partly re-oxidised in the subsequent second ODP run of the reaction cycle. The partly re-oxidised species exhibit oxidation and coordination states that are lower than 6 but higher than 4 and are referred to as MoxOy. These species significantly improved propene formation (relatively 27% higher) in the second ODP run at similar propane conversion activity. Accordingly, the initial tetrahedral [MoVIO4]2− present during the first ODP run of the reaction cycle is active for propane conversion; however, it is unselective for propene. The reduced MoIVO2 species are relatively less active and selective for DP. It is suggested that the MoxOy species generated by the reaction cycle are active and selective for ODP. The vibrational spectroscopic data indicate that the retained surface species are amorphous carbon deposits with a higher proportion of aromatic/olefinic like species

    Theoretical Models of Sunspot Structure and Dynamics

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    Recent progress in theoretical modeling of a sunspot is reviewed. The observed properties of umbral dots are well reproduced by realistic simulations of magnetoconvection in a vertical, monolithic magnetic field. To understand the penumbra, it is useful to distinguish between the inner penumbra, dominated by bright filaments containing slender dark cores, and the outer penumbra, made up of dark and bright filaments of comparable width with corresponding magnetic fields differing in inclination by some 30 degrees and strong Evershed flows in the dark filaments along nearly horizontal or downward-plunging magnetic fields. The role of magnetic flux pumping in submerging magnetic flux in the outer penumbra is examined through numerical experiments, and different geometric models of the penumbral magnetic field are discussed in the light of high-resolution observations. Recent, realistic numerical MHD simulations of an entire sunspot have succeeded in reproducing the salient features of the convective pattern in the umbra and the inner penumbra. The siphon-flow mechanism still provides the best explanation of the Evershed flow, particularly in the outer penumbra where it often consists of cool, supersonic downflows.Comment: To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200
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