510 research outputs found

    New specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 from the Early Jurassic of South Africa

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    We describe new specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 collected from a bonebed in the Fouriesburg district of the Free State, South Africa. The material was collected from the upper Elliot Formation (Early Jurassic) and represents the remains of at least three individuals. These individuals are larger in body size than those already known in museum collections and offer additional information on cranial ontogeny in the taxon. Moreover, they are similar in size to the sympatric taxon Stormbergia dangershoeki. The discovery of three individuals at this locality might imply group-living behaviour in this early ornithischian.Palaeontologia africana 2016. ©2016 Paul M. Barrett, Richard J. Butler, Adam M. Yates, Matthew G. Baron&Jonah N. Choiniere. This is an open-access article published under the Creative Commons Attribution 4.0 Unported License (CC BY4.0). To view a copy of the license, please visit http://creativecommons.org/licenses/by/4.0/. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This item is permanently archived at: http://wiredspace.wits.ac.za/handle/10539/19886. The attached file is the published version of the article

    Tomographic reconstruction of neopterous Carboniferous insect nymphs

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    Two new polyneopteran insect nymphs from the Montceau-les-Mines LagerstĂ€tte of France are presented. Both are preserved in three dimensions, and are imaged with the aid of X-ray micro-tomography, allowing their morphology to be recovered in unprecedented detail. One–Anebos phrixos gen. et sp. nov.–is of uncertain affinities, and preserves portions of the antennae and eyes, coupled with a heavily spined habitus. The other is a roachoid with long antennae and chewing mouthparts very similar in form to the most generalized mandibulate mouthparts of extant orthopteroid insects. Computer reconstructions reveal limbs in both specimens, allowing identification of the segments and annulation in the tarsus, while poorly developed thoracic wing pads suggest both are young instars. This work describes the morphologically best-known Palaeozoic insect nymphs, allowing a better understanding of the juveniles’ palaeobiology and palaeoecology. We also consider the validity of evidence from Palaeozoic juvenile insects in wing origin theories. The study of juvenile Palaeozoic insects is currently a neglected field, yet these fossils provide direct evidence on the evolution of insect development. It is hoped this study will stimulate a renewed interest in such work

    Correlates of work injury frequency and duration among firefighters.

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    Co-operation in Health and Safety: A Game Theory Analysis

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    [Excerpt] “Health and safety managers face complex challenges in today’s production environments. They are confronted with increasingly flexible, autonomous and polyvalent contexts. Asymmetry of information on the workplace is widespread because various intervening parties rely on information lacking conformity. Social partners generate and use information which supports or benefits their pursuit of differing goals. Ascertaining and controlling this information can prove both difficult and costly. When addressing health and safety issues, one intervening partner alters or changes behavior in response to changes introduced by the other side. Strategic behaviors result, based on post-contract opportunism (moral hazard) and alliances with partners who can reasonably be expected to deliver predictable and effective contributions toward individual goals (adverse selection). These behaviors arise out of diagnostic problems, difficulty in determining acceptable risk, asymmetries in the information used in risk taking decisions on the part of social partners and the operation of health and safety systems. . . . Inevitably, effective and efficient management of health and safety must spring from an understanding of the dynamics governing the intervening parties. This paper makes use of non-cooperative game theory to identify conditions fostering cooperation between managers and workers as social partners in the workplace.

    Dedication

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    Unions and the decision to apply for and the receipt of workers' compensation benefits

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    Using a unique set of questions in the National Longitudinal Survey of Youth 1979 provides some direct evidence on the mechanism through which union coverage increases WC receipt. Delineating the effects of unions on the decision to apply and the receipt of WC benefits reveals that unions substantially increase the probability of applying conditional on injury, but decrease the probability of receipt conditional on applying.union; workers' compensation; injuries; benefits
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