704 research outputs found

    Book Reviews

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    Book Review 1Book Title: The Springbok Antidorcas marsupialis (Zimmerman, 1780)Book Authors: J.D. Skinner & G.N. LouwTransvaal Museum Monograph No.1 0, 1996. 49 pp. ISBN 0 907990 169.Book Review 2Book Title: Ecomorphology of fishesBook Authors: Luczkovich, J.J., Motta, P.J., Norton, S.F. & Liem, K.F. (Editors)Dordrecht: Kluwer, 1995. 312 pp.. ISBN 0 7923 3744 1Book Review 3Book Title: Africa: a natural historyBook Authors: Chris & Tilde StuartSouthern Book Publishers, 1995. Price: R130.00

    Iris colour in passerine birds: why be bright-eyed?

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    An initial survey of iris coloration in passerine birds (Aves: Passeriformes) showed that a brightly pigmented iris is much more common in southern African and Australian birds than in those from Europe, temperate North America, and Venezuela. However, the only statistical correlation reflected the distribution of particular bird families in these regions. Ten family-level groups considered to represent monophyletic taxa were then selected for a more detailed analysis, comparing iris coloration with distribution, status, taxonomy, plumage patterns, and some biological and behavioural characters for 1143 species. No pattern associating iris colour with particular traits was common to all families, but within families there were statistically significant associations with both plumage and biology. Our expectation that social behaviour would be an important predictor of iris colour was not supported, but critical information is still lacking for many species. Future studies of avian behavioural ecology should examine critically the role of iris coloration in individual species.Rhodes Centenary issu

    Platelet rich Plasma in Achilles Tendon Healing 2 (PATH-2) trial: protocol for a multicentre, participant and assessor-blinded, parallel-group randomised clinical trial comparing platelet-rich plasma (PRP) injection versus placebo injection for Achilles tendon rupture

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    BackgroundAchilles tendon injuries give rise to substantial long-lasting morbidity and pose considerable challenges for clinicians and patients during the lengthy healing period. Current treatment strategies struggle to curb the burden of this injury on health systems and society due to lengthy rehabilitation, work absence and reinjury risk. Platelet-rich plasma (PRP) is an autologous preparation that has been shown to improve the mechanobiological properties of tendons in laboratory and animal studies. The use of PRP in musculoskeletal injuries is on the increase despite the lack of adequately powered clinical studies.Methods and designThis is a multicentre randomised controlled trial to evaluate the efficacy and mechanism of PRP in patients with acute Achilles tendon rupture (ATR). All adults with acute ATR presenting within 12 days of the injury who are to be treated non-operatively are eligible. A total of 230 consenting patients will be randomly allocated via a remote web-based service to receive PRP injection or placebo injection to the site of the injury. All participants will be blinded to the intervention and will receive standardised rehabilitation to reduce efficacy interference.Participants will be followed up with blinded assessments of muscle–tendon function, quality of life, pain and overall patient’s functional goals at 4, 7, 13, 24 weeks and 24 months post-treatment. The primary outcome is the heel-rise endurance test (HRET), which will be supervised by a blinded assessor at 24 weeks. A subgroup of 16 participants in one centre will have needle biopsy under ultrasound guidance at 6 weeks. Blood and PRP will be analysed for cell count, platelet activation and growth factor concentrations.Ethics and disseminationThe protocol has been approved by the Oxfordshire Research Ethics Committee (Oxfordshire Research Ethics Committee A, reference no 14/SC/1333). The trial will be reported in accordance with the CONSORT statement and published in peer-reviewed scientific journals.Trial registration numberISRCTN: 54992179, assigned 12 January 2015. ClinicalTrials.gov:NCT02302664, received 18 November 2014. UK Clinical Research Network Study Portfolio Database: ID 17850.</jats:sec

    Platelet rich plasma injection for acute Achilles tendon rupture: PATH-2 randomised, placebo controlled, superiority trial

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    This is the final version. Available on open access from BMJ Publishing via the DOI in this record. Objective To determine whether an injection of platelet rich plasma improves outcomes after acute Achilles tendon rupture. Design Randomised, placebo controlled, two arm, parallel group, participant and assessor masked, superiority trial. Setting Secondary care trauma units across 19 hospitals in the United Kingdom's health service. Participants Recruitment commenced in July 2015 and follow-up was completed in March 2018. 230 adults aged 18 years and over were included, with acute Achilles tendon rupture presenting within 12 days of injury and managed with non-surgical treatment. Exclusions were injury at the insertion or musculotendinous junction, major leg injury or deformity, diabetes mellitus, platelet or haematological disorder, systemic corticosteroids, anticoagulation treatment, and other contraindicating conditions. Interventions Participants were randomised 1:1 to platelet rich plasma (n=114) or placebo (dry needle; n=116) injection. All participants received standard rehabilitation care (ankle immobilisation followed by physiotherapy). Main outcomes and measures Primary outcome was muscle tendon function at 24 weeks, measured objectively with the limb symmetry index (injured/uninjured×100) in maximal work done during the heel rise endurance test (an instrumented measure of repeated single leg heel rises until fatigue). Secondary outcomes included patient reported function (Achilles tendon rupture score), quality of life (short form 12 version 2®), pain (visual analogue scale), goal attainment (patient specific functional scale), and adverse events. A central laboratory analysed the quality and content of platelet rich plasma. Analyses were by modified intention to treat. Results Participants were 46 years old on average, and 57 (25%) of 230 were female. At 24 weeks, 202 (88%) participants completed the heel rise endurance test and 216 (94%) the patient reported outcomes. The platelet rich plasma was of good quality, with expected growth factor content. No difference was detected in muscle tendon function between participants receiving platelet rich plasma injections and those receiving placebo injections (limb symmetry index, mean 34.7% (standard deviation 17.7%) v 38.5% (22.8%); adjusted mean difference -3.9% (95% confidence interval -10.5% to 2.7%)) or in any secondary outcomes or adverse event rates. Complier average causal effect analyses gave similar findings. Conclusions There is no evidence to indicate that injections of platelet rich plasma can improve objective muscle tendon function, patient reported function, or quality of life after acute Achilles tendon rupture compared with placebo, or that they offer any patient benefit. Trial registration ISRCTN54992179.Efficacy and Mechanism Evaluation programme, a Medical Research Council (MRC) and National Institute for Health Research (NIHR) partnershi

    Genetic and morphological variation of the lanternfish lampanyctodes hectoris (myctophiformes: myctophidae) off Southern Africa

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    Genetic and morphological variation within the southern African population of Lampanyctodes hectoris was analysed. A total of 15 enzymes, encoding 22 isozyme loci, was examined (n = 327); seven were polymorphic. The percentage of polymorphic loci ranged from 13.6 to 27.3%. The mean heterozygosity was generally low and ranged from 0.003 to 0.005. Genetic divergences between specimens from four areas along the west coast of southern Africa were negligible, genetic distance values (D) ranging from 0 to 0.00011. The results showed the population of L. hectoris to be genetically invariant. Principal Component Analysis was performed separately on ratios of 13 morphometric and 6 meristic variables (n = 446), and there was evidence of extensive overlap between fish from all areas. However, discriminant analysis suggested some morphological variability within this population. Although genetically the population of L. hectoris seems to be homogenous, morphologically it appears to be variable. A combination of these results suggests that there is no clear genetic basis for the slight morphological differentiation within the population

    Platelet-rich plasma injection for adults with acute Achilles tendon rupture: the PATH-2 RCT

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    BACKGROUND:Achilles tendon rupture (ATR) has a long healing period, which is challenging for patients and clinicians. Platelet-rich plasma (PRP) is an autologous concentration of platelets thought to improve tendon function recovery. Although preliminary research has indicated positive effects, there is, as yet, no evidence of clinical efficacy from adequately powered robust clinical trials. OBJECTIVES:The objectives were to determine the clinical efficacy of PRP in patients with acute ATR using an objective mechanical muscle–tendon function measure and patient-reported outcome measures (PROMs), and to determine which PRP components contribute to its mechanism. DESIGN:This was a multicentre, parallel-group, participant- and outcome assessor-blinded randomised controlled trial (RCT) comparing PRP with placebo. Two embedded substudies investigated the PRP’s quality and composition and its effects on healing tendon tissues. SETTING:This trial was set in trauma and orthopaedic surgery departments in 19 NHS hospitals in England and Wales. PARTICIPANTS:Adults with acute ATR presenting within 12 days of injury to be treated non-surgically were eligible. Patients with platelet dysfunction or leg functional deficiency were excluded. INTERVENTIONS:Participants were randomised 1 : 1 to the PRP injection group or the placebo group (dry needle in the rupture gap) by central computer-based randomisation using minimisation, stratified by centre and age. MAIN OUTCOME MEASURES:The primary outcome measure was the Limb Symmetry Index (LSI) of work during the heel-rise endurance test at 24 weeks. Secondary outcomes measures, collected at 4, 7, 13 and 24 weeks, were repetitions, maximum heel-rise height, Achilles tendon Total Rupture Score (ATRS), quality of life (as measured using the Short Form questionnaire-12 items version 2), pain and participant goal attainment. Needle biopsies of the affected tendon zone were taken under ultrasound guidance at 6 weeks from 16 participants from one centre. Whole blood was analysed for cell count. PRP was analysed for cell count, platelet activation and growth factor concentration. The primary analysis was intention to treat. RESULTS:A total of 230 participants were randomised: 114 to the PRP group (103 treated) and 116 to the placebo group (all treated). One participant withdrew after randomisation but before the intervention. At 24 weeks, 201 out of 230 participants (87.4%) completed the primary outcome and 216 out of 230 participants (93.9%) completed the PROMs. The treatment groups had similar participant characteristics. At 24 weeks, there was no difference in work LSI (mean difference –3.872; 95% confidence interval –10.454 to 2.710; p = 0.231), ATRS, pain or goal attainment between PRP- and placebo-injected participants. There were no differences between the groups in any PROM at any time point or in complication rates, including re-rupture and deep-vein thrombosis. There was no correlation between work LSI and platelet activation in PRP, or erythrocyte, leucocyte or platelet counts in whole blood or PRP. Biopsies showed similar cellularity and vascularity between groups. CONCLUSIONS:This trial design and standardised PRP preparation gives the first robust RCT evidence about PRP’s role in managing ATR, which suggests that PRP offers no patient benefit. Equally robust evidence to investigate PRP application in tendon and soft tissue injuries is required. The 24-month follow-up will be completed in April 2020. TRIAL REGISTRATION:Current Controlled Trials ISRCTN54992179. FUNDING:This project was funded by the Efficacy and Mechanism Evaluation programme, a Medical Research Council and National Institute for Health Research (NIHR) partnership. The trial was supported by the NIHR Biomedical Research Centre, Oxford, and the NIHR Fellowship programme

    On arbitrages arising from honest times

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    In the context of a general continuous financial market model, we study whether the additional information associated with an honest time gives rise to arbitrage profits. By relying on the theory of progressive enlargement of filtrations, we explicitly show that no kind of arbitrage profit can ever be realised strictly before an honest time, while classical arbitrage opportunities can be realised exactly at an honest time as well as after an honest time. Moreover, stronger arbitrages of the first kind can only be obtained by trading as soon as an honest time occurs. We carefully study the behavior of local martingale deflators and consider no-arbitrage-type conditions weaker than NFLVR.Comment: 25 pages, revised versio
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