45 research outputs found

    Do Lions Panthera leo Actively Select Prey or Do Prey Preferences Simply Reflect Chance Responses via Evolutionary Adaptations to Optimal Foraging?

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    Research on coursing predators has revealed that actions throughout the predatory behavioral sequence (using encounter rate, hunting rate, and kill rate as proxy measures of decisions) drive observed prey preferences. We tested whether similar actions drive the observed prey preferences of a stalking predator, the African lion Panthera leo. We conducted two 96 hour, continuous follows of lions in Addo Elephant National Park seasonally from December 2003 until November 2005 (16 follows), and compared prey encounter rate with prey abundance, hunt rate with prey encounter rate, and kill rate with prey hunt rate for the major prey species in Addo using Jacobs' electivity index. We found that lions encountered preferred prey species far more frequently than expected based on their abundance, and they hunted these species more frequently than expected based on this higher encounter rate. Lions responded variably to non-preferred and avoided prey species throughout the predatory sequence, although they hunted avoided prey far less frequently than expected based on the number of encounters of them. We conclude that actions of lions throughout the predatory behavioural sequence, but particularly early on, drive the prey preferences that have been documented for this species. Once a hunt is initiated, evolutionary adaptations to the predator-prey interactions drive hunting success

    A new, large-bodied omnivorous bat (Noctilionoidea: Mystacinidae) reveals lost morphological and ecological diversity since the Miocene in New Zealand

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    A new genus and species of fossil bat is described from New Zealand's only pre-Pleistocene Cenozoic terrestrial fauna, the early Miocene St Bathans Fauna of Central Otago, South Island. Bayesian total evidence phylogenetic analysis places this new Southern Hemisphere taxon among the burrowing bats (mystacinids) of New Zealand and Australia, although its lower dentition also resembles Africa's endemic sucker-footed bats (myzopodids). As the first new bat genus to be added to New Zealand's fauna in more than 150 years, it provides new insight into the original diversity of chiropterans in Australasia. It also underscores the significant decline in morphological diversity that has taken place in the highly distinctive, semi-terrestrial bat family Mystacinidae since the Miocene. This bat was relatively large, with an estimated body mass of ~40 g, and its dentition suggests it had an omnivorous diet. Its striking dental autapomorphies, including development of a large hypocone, signal a shift of diet compared with other mystacinids, and may provide evidence of an adaptive radiation in feeding strategy in this group of noctilionoid bats

    Racism as a determinant of health: a systematic review and meta-analysis

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    Despite a growing body of epidemiological evidence in recent years documenting the health impacts of racism, the cumulative evidence base has yet to be synthesized in a comprehensive meta-analysis focused specifically on racism as a determinant of health. This meta-analysis reviewed the literature focusing on the relationship between reported racism and mental and physical health outcomes. Data from 293 studies reported in 333 articles published between 1983 and 2013, and conducted predominately in the U.S., were analysed using random effects models and mean weighted effect sizes. Racism was associated with poorer mental health (negative mental health: r = -.23, 95% CI [-.24,-.21], k = 227; positive mental health: r = -.13, 95% CI [-.16,-.10], k = 113), including depression, anxiety, psychological stress and various other outcomes. Racism was also associated with poorer general health (r = -.13 (95% CI [-.18,-.09], k = 30), and poorer physical health (r = -.09, 95% CI [-.12,-.06], k = 50). Moderation effects were found for some outcomes with regard to study and exposure characteristics. Effect sizes of racism on mental health were stronger in cross-sectional compared with longitudinal data and in non-representative samples compared with representative samples. Age, sex, birthplace and education level did not moderate the effects of racism on health. Ethnicity significantly moderated the effect of racism on negative mental health and physical health: the association between racism and negative mental health was significantly stronger for Asian American and Latino(a) American participants compared with African American participants, and the association between racism and physical health was significantly stronger for Latino(a) American participants compared with African American participants.<br /

    Palynology of Jurassic (Bathonian) sediments from Donbas, northeast Ukraine

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    A palynological and sedimentological study of an outcrop succession adjacent to the village of Kamyanka within the Kharkiv region of northeast Ukraine was carried out. The successions occur within the Dnieper–Donets Basin, which hosts vast successions (&gt; 20 km) of post mid- Devonian strata and is one of the main hydrocarbonproducing basins in Europe. Middle Jurassic sandstones, siltstones and claystones represent the sedimentary successions at the Kamyanska locality. Few palynological studies have been performed on the Jurassic of Ukraine and even fewer presented in the international literature. Thirty spore taxa and 21 pollen taxa were identified, together with taxa kept in open nomenclature (e.g. bisaccate pollen). Two palynological assemblages were identified within the Kamyanska succession (assemblages A and B) dated as Bathonian. Assemblage A is dominated by the fern spores (Cyathidites and Osmundacidites) and gymnosperm pollen produced by Cupressaceae Perinopollenites elatoides), ginkgophytes/Cycadales/Bennettitales (monosulcates) and Cheirolepidiaceae (Classopollis). Assemblage B differs in also comprising high abundances of Gleicheniidites and higher percentages of Pinuspollenites and Araucariacites compared to assemblage A. Another difference between the two units is the high relative abundance of seed fern pollen (Alisporites) in the upper part of assemblage B. The thermal alteration index (TAI) of the palynomorphs is estimated to range from 3 to 3.5, indicating a burial depth corresponding to the mature main phase of liquid petroleum and, to some extent, gas generation. Comparisons between the miospore and macrofloral assemblages show that the palynoflora and macroflora are strongly similar at broad taxonomic levels. Importantly, the miospore assemblages described here compare well with European Middle Jurassic assemblages indicating limited provincialism, with similar vegetation extending from eastern Ukraine and across most of Western Europe.The authors acknowledge the Karazin Kharkiv National University, the host organisation of the 100th anniversary of V.P. Makrydin during which the samples were collected. This is a contribution to the UNESCO/IGCP project 632, Continental Crises of the Jurassic: Major Extinction Events and Environmental Changes Within Lacustrine Ecosystems. The authors further acknowledge the support of the Swedish Research Council (Research links, 2013-6702), for O.S. and V.V. and that of Lund University Carbon Centre (LUCCI) for S.S. and V.V.</p

    The vascularised fibular graft for limb salvage after bone tumour surgery

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    Vascularised fibular grafts (VFGs) are a valuable surgical technique in limb salvage after resection of a tumour. The primary objective of this multicentre study was to assess the risk factors for failure and complications for using a VFG after resection of a tumour. The study involved 74 consecutive patients (45 men and 29 women with mean age of 23 years (1 to 64) from four tertiary centres for orthopaedic oncology who underwent reconstruction using a VFG after resection of a tumour between 1996 and 2011. There were 52 primary and 22 secondary reconstructions. The mean follow-up was 77 months (10 to 195). In all, 69 patients (93%) had successful limb salvage; all of these united and 65 (88%) showed hypertrophy of the graft. The mean time to union differed between those involving the upper (28 weeks; 12 to 96) and lower limbs (44 weeks; 12 to 250). Fracture occurred in 11(15%), and nonunion in 14 (19%) patients. In 35 patients (47%) at least one complication arose, with a greater proportion in lower limb reconstructions, non-bridging osteosynthesis, and in children. These complications resulted in revision surgery in 26 patients (35%). VFG is a successful and durable technique for reconstruction of a defect in bone after resection of a tumour, but is accompanied by a significant risk of complications, that often require revision surgery. Union was not markedly influenced by the need for chemo- or radiotherapy, but should not be expected during chemotherapy. Therefore, restricted weight-bearing within this period is advocate
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