41 research outputs found

    On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness

    Get PDF
    The size and flight mechanics of giant pterosaurs have received considerable research interest for the last century but are confused by conflicting interpretations of pterosaur biology and flight capabilities. Avian biomechanical parameters have often been applied to pterosaurs in such research but, due to considerable differences in avian and pterosaur anatomy, have lead to systematic errors interpreting pterosaur flight mechanics. Such assumptions have lead to assertions that giant pterosaurs were extremely lightweight to facilitate flight or, if more realistic masses are assumed, were flightless. Reappraisal of the proportions, scaling and morphology of giant pterosaur fossils suggests that bird and pterosaur wing structure, gross anatomy and launch kinematics are too different to be considered mechanically interchangeable. Conclusions assuming such interchangeability—including those indicating that giant pterosaurs were flightless—are found to be based on inaccurate and poorly supported assumptions of structural scaling and launch kinematics. Pterosaur bone strength and flap-gliding performance demonstrate that giant pterosaur anatomy was capable of generating sufficient lift and thrust for powered flight as well as resisting flight loading stresses. The retention of flight characteristics across giant pterosaur skeletons and their considerable robustness compared to similarly-massed terrestrial animals suggest that giant pterosaurs were not flightless. Moreover, the term ‘giant pterosaur’ includes at least two radically different forms with very distinct palaeoecological signatures and, accordingly, all but the most basic sweeping conclusions about giant pterosaur flight should be treated with caution. Reappraisal of giant pterosaur material also reveals that the size of the largest pterosaurs, previously suggested to have wingspans up to 13 m and masses up to 544 kg, have been overestimated. Scaling of fragmentary giant pterosaur remains have been misled by distorted fossils or used inappropriate scaling techniques, indicating that 10–11 m wingspans and masses of 200–250 kg are the most reliable upper estimates of known pterosaur size

    The Long Term Response of Birds to Climate Change: New Results from a Cold Stage Avifauna in Northern England

    Get PDF
    The early MIS 3 (55–40 Kyr BP associated with Middle Palaeolithic archaeology) bird remains from Pin Hole, Creswell Crags, Derbyshire, England are analysed in the context of the new dating of the site’s stratigraphy. The analysis is restricted to the material from the early MIS 3 level of the cave because the upper fauna is now known to include Holocene material as well as that from the Late Glacial. The results of the analysis confirm the presence of the taxa, possibly unexpected for a Late Pleistocene glacial deposit including records such as Alpine swift, demoiselle crane and long-legged buzzard with southern and/or eastern distributions today. These taxa are accompanied by more expected ones such as willow ptarmigan /red grouse and rock ptarmigan living today in northern and montane areas. Finally, there are temperate taxa normally requiring trees for nesting such as wood pigeon and grey heron. Therefore, the result of the analysis is that the avifauna of early MIS 3 in England included taxa whose ranges today do not overlap making it a non-analogue community similar to the many steppe-tundra mammalian faunas of the time. The inclusion of more temperate and woodland taxa is discussed in the light that parts of northern Europe may have acted as cryptic northern refugia for some such taxa during the last glacial. These records showing former ranges of taxa are considered in the light of modern phylogeographic studies as these often assume former ranges without considering the fossil record of those taxa. In addition to the anomalous combination of taxa during MIS 3 living in Derbyshire, the individuals of a number of the taxa are different in size and shape to members of the species today probably due to the high carrying capacity of the steppe-tundra

    The mechanisms of action of vaccines containing aluminum adjuvants: an in vitro vs in vivo paradigm

    Get PDF

    Foucault, sustainable tourism, and relationships with the environment (human and nonhuman)

    No full text
    Drawing on contemporary research into ethical consumption and sustainable tourism this article starts by outlining the ways in which sustainable tourism (and other forms of ethical consumption) has been understood as a means to perform class based distinctions. At this stage, it is suggested that whilst class may be one factor in understanding such a complex phenomena there might also be a need to examine the practices of sustainable tourist in a manner that takes seriously individual attempts to ‘be ethical’. Foucault’s understanding of ethics is then offered as a means through which this can be achieved. A brief account of the method used to read individuals accounts of sustainable tourism through an ethical Foucauldian lens is then presented. Following this the paper presents the analysis of interviews with sustainable tourists focusing on two key elements. Firstly, the analysis presents the emotional and reciprocal elements of interactions between sustainable tourists and the human ‘other’. Secondly the analysis examines the relationship between the sustainable tourist and non-human environments to further develop the understanding of the emotional and reciprocal elements in light of a Foucauldian ethics. In conclusion it is suggested that rather than merely representing a mode of class distinction, sustainable tourism can be understood through an appreciation of the emotional and reciprocal relationship with the other, thus taking seriously individuals attempts to engage with ethical practices
    corecore