413,573 research outputs found
A comparison between dinosaur footprints from the Middle Jurassic of the Isle of Skye, Scotland, UK, and Shell, Wyoming, USA
Measurements of Middle Jurassic tridactyl dinosaur tracks from the Bathonian, Lealt Shale, Valtos Sandstone, Duntulm and Kilmaluag formations of the Isle of Skye, UK, are compared to the same measurements taken for dinosaur footprints from the Bajocian, Gypsum Spring and the Bathonian, Sundance Formation of the Bighorn Basin, Wyoming, USA. Principal component analysis of the data suggests that the smaller footprints from the Valtos Sandstone and Kilmaluag formations are indistinguishable from the footprints of the Sundance Formation. The single footprint from the Lealt Shale Formation is similar to the larger footprints from the Valtos Sandstone Formation. The footprints from the Duntulm and Gypsum Springs formations form distinct groupings from all other footprints. Four different groupings of dinosaur footprints can be recognized from the principal component analysis that may represent at least four different types of dinosaur
Evolution and change in palliative care around the world
Palliative care developed in the later part of the 20th century as a social movement and medical speciality. Central to its modern development were the ideas of Dr Cicely Saunders, whose vision for improving the care of the dying encompassed the physical, psychological, social and spiritual domains while emphasizing the importance of rigorous clinical practice, training and research. St Christopher’s Hospice, which she founded, inspired generations of practitioners and influenced the expansion of hospices nationally and internationally. Terminal care evolved into the discipline of palliative care, which applied holistic principles to the care of those earlier in their disease trajectory and in different settings, such as hospitals and the community. Some countries now have national strategies for palliative care that are supported by government. Palliative care attracts increasing attention as an aspect of the public health system and there are calls for access to it to be recognized as a human right. Yet around the world, palliative care is not uniformly developed and it needs to press hard to secure full integration with prevailing health policies. Palliative care still reaches only a tiny proportion of those who could benefit from it, especially those with diseases other than cancer. The global challenge for palliative care in the 21st century is to develop models and coverage appropriate to those in need, whatever their diagnosis, income or setti
Westerlund 1 as a Template for Massive Star Evolution
With a dynamical mass M_dyn ~ 1.3x10e5 M_sun and a lower limit M_cl>5x10e4
M_sun from star counts, Westerlund 1 is the most massive young open cluster
known in the Galaxy and thus the perfect laboratory to study massive star
evolution. We have developed a comprehensive spectral classification scheme for
supergiants based on features in the 6000-9000A range, which allows us to
identify >30 very luminous supergiants in Westerlund 1 and ~100 other less
evolved massive stars, which join the large population of Wolf-Rayet stars
already known. Though detailed studies of these stars are still pending,
preliminary rough estimates suggest that the stars we see are evolving to the
red part of the HR diagram at approximately constant luminosity.Comment: To be published in Proceedings of IAU Symposium 250: Massive Stars as
Cosmic Engines, held in Kaua'i (Hawaii, USA), Dec 2007, edited by F.
Bresolin, P.A. Crowther & J. Puls (Cambridge University Press
Sheep, dingoes and kangaroos: new challenges and a change of direction 20 years on
Predation and competition are two primary forces limiting the extent to which sheep can be grazed in the Australian rangelands, particularly in Queensland. Dingo predation has been non-existent in much of the sheep zone since the localised eradication of dingoes in the early 1900s. Competition with kangaroos has been ever-present, but was previously managed (to some extent) by the commercial kangaroo harvesting industry. However, changes to dingo distribution and kangaroo densities and harvesting over the last 20 years have meant that dingo predation and kangaroo competition again threaten viable sheep production in the rangelands. Dingoes have increased their distribution and density in almost all sheep grazing areas and contemporary lethal control efforts are not preventing the decline of sheep. Loss of valuable international markets and moves to now harvest only adult male kangaroos means that the kangaroo harvesting industry produces little relief from kangaroo grazing pressure (given that kangaroo population growth is little affected by removal of adult males; see Finch et al. this volume). New approaches to dingo and kangaroo management are sorely needed to salvage and restore the production of sheep in the rangelands. In response, the installation and use of pest-proof fences is rapidly increasing in Queensland and other areas, facilitating, for the first time in nearly a century, the localised eradication of dingoes and the suppression of kangaroos to manageable numbers within fenced areas. We describe these challenges and opportunities for one site in particular (Leander Station), and offer a sheep grazier’s perspective on past and future use and management of problematic wildlife in sheep production zones
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