6,311 research outputs found

    Obituary: Arthur Cruickshank 1932 - 2011. A native Gondwanan, who studied the former continent's fossil tetrapods

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    Dr Arthur Richard Ivor Cruickshank died on 4th December 2011, aged 79, in the Borders General Hospital, Melrose, Scotland. Arthur Cruickshank was part of the post-war generation of palaeontologists who laid the foundations on which today’s researchers build. Appropriately for someone from an expatriate Scots family living in Kenya, much of his work was on the extinct reptiles of the great southern palaeocontinent of Gondwana

    Macroevolutionary Patterns In The Evolutionary Radiation Of Archosaurs (Tetrapoda: Diapsida)

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    The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassic. The fundamental archosaur lineages originated early in the Triassic, in concert with the highest rates of character change. Disparity and diversity peaked later, during the Norian, but the most significant increase in disparity occurred before maximum diversity. Archosaurs were rare components of Early–Middle Triassic faunas, but were more abundant in the Late Triassic and pre-eminent globally by the Early Jurassic. The archosaur radiation was a drawn-out event and major components such as diversity and abundance were discordant from each other. Crurotarsans (crocodile-line archosaurs) were more disparate, diverse, and abundant than avemetatarsalians (bird-line archosaurs, including dinosaurs) during the Late Triassic, but these roles were reversed in the Early Jurassic. There is no strong evidence that dinosaurs outcompeted or gradually eclipsed crurotarsans during the Late Triassic. Instead, crurotarsan diversity decreased precipitously by the end-Triassic extinction, which helped usher in the age of dinosaurian dominance

    Systems Analysis Using the Transtheoretical Model of Behavioral Change: Encouraging Adoption of Best Practices Over Standard Practices

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    This paper describes a novel approach to systems analysis and design (SA&D) based upon the transtheoretical model of behavioral change (TTM). TTM was developed for the purpose of helping clinicians and patients change behaviors related to health such as smoking and exercise. The application of TTM to SA&D described here is appropriate when one of the key rationales for developing a new system is to alter user behavior with respect to task performance, particularly when use of the system will be optional. The key strengths of TTM include a structured approach to understanding behavioral change, concrete metrics that can be developed to measure specific behavioral change processes, and clear guidelines for the use and timing of various mechanisms for fostering change. This paper describes a system design in the field of educational technology designed to foster the use of best practices with respect to multiple-choice question writing, delivery, and analysis
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