3,121 research outputs found

    Tackling the Tibetan Plateau in a down suit: Insights into thermoregulation by bar-headed geese during migration

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    This is the final version. Available from Company of Biologists via the DOI in this recordData accessibility: Following the manuscript being accepted data will be uploaded to a public repository such as Dryad.Birds migrating through extreme environments can experience a range of challenges while matching the demands of flight, including highly variable ambient temperatures, humidity and oxygen levels. However, there has been limited research into avian thermoregulation during migration in extreme environments. This study aimed to investigate the effect of flight performance and high-altitude on body temperature (Tb) of free flying bar-headed geese (Anser indicus), a species that completes a high-altitude trans-Himalayan migration through very cold, hypoxic environments. We measured abdominal Tb, along with altitude (via changes in barometric pressure), heart rate and body acceleration of bar-headed geese during their migration across the Tibetan Plateau. Bar-headed geese vary the circadian rhythm of Tb in response to migration, with peak daily Tb during daytime hours outside of migration but early in the morning or overnight during migration, reflecting changes in body acceleration. However, during flights changes in Tb were not consistent with changes in flight performance (as measured by heart rate or rate of ascent) or altitude. Overall, our results suggest that bar-headed geese are able to thermoregulate during high-altitude migration, maintaining Tb within a relatively narrow range despite appreciable variation in flight intensity and environmental conditions.Biotechnology and Biological Sciences Research Council (BBSRC)Natural Sciences and Engineering Research Council of Canada (NSERC)Max Planck Institute for OrnithologyUS Geological SurveyWestern Ecological and Patuxent Wildlife Research Centers, Avian Influenza Programm

    Increased Aβ pathology in aged Tg2576 mice born to mothers fed a high fat diet

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    Maternal obesity is associated with increased risk of developing diabetes, obesity and premature death in adult offspring. Mid-life diabetes, hypertension and hypercholesterolaemia are risk factors for the development of sporadic Alzheimer's disease (AD). A key pathogenic feature of AD is the accumulation of β-amyloid (Aβ) in the brain. The purpose of this study was to investigate the effect of high fat diet feeding during early life on Aβ pathology in the Tg2576 mouse model of AD. Female mice were fed a standard (C) or high fat (HF) diet before mating and during gestation and lactation. At weaning, male offspring were fed a C diet. Significantly higher levels of guanidine-soluble Aβ and plaque loads were observed in the hippocampi of 11-month old Tg2576 mice born to mothers fed a HF diet. Changes in the extracellular matrix led to increased retention of Aβ within the parenchyma. These data support a role for maternal and gestational health on the health of the aged brain and pathologies associated with AD and may provide a novel target for both the prevention and treatment of AD

    Do Bar-Headed Geese Train for High Altitude Flights?

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    This is the author accepted manuscript. The final version is available from OUP via the DOI in this recordSYNOPSIS: Exercise at high altitude is extremely challenging, largely due to hypobaric hypoxia (low oxygen levels brought about by low air pressure). In humans, the maximal rate of oxygen consumption decreases with increasing altitude, supporting progressively poorer performance. Bar-headed geese (Anser indicus) are renowned high altitude migrants and, although they appear to minimize altitude during migration where possible, they must fly over the Tibetan Plateau (mean altitude 4800 m) for much of their annual migration. This requires considerable cardiovascular effort, but no study has assessed the extent to which bar-headed geese may train prior to migration for long distances, or for high altitudes. Using implanted loggers that recorded heart rate, acceleration, pressure, and temperature, we found no evidence of training for migration in bar-headed geese. Geese showed no significant change in summed activity per day or maximal activity per day. There was also no significant change in maximum heart rate per day or minimum resting heart rate, which may be evidence of an increase in cardiac stroke volume if all other variables were to remain the same. We discuss the strategies used by bar-headed geese in the context of training undertaken by human mountaineers when preparing for high altitude, noting the differences between their respective cardiovascular physiology.This work was supported by the UK Biotechnology and Biological Sciences Research Council [BBSRC; BB/FO15615/1 to C.M.B. and P.J.B.]. Authors were supported by a Natural Sciences and Engineering Research Council of Canada (NSERC) award [W.K.M.], and the FAO through the Animal Health Service EMPRES surveillance program

    Use and limitations of malaria rapid diagnostic testing by community health workers in war-torn Democratic Republic of Congo

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    <p>Abstract</p> <p>Background</p> <p>Accurate and practical malaria diagnostics, such as immunochromatographic rapid diagnostic tests (RDTs), have the potential to avert unnecessary treatments and save lives. Volunteer community health workers (CHWs) represent a potentially valuable human resource for expanding this technology to where it is most needed, remote rural communities in sub-Saharan Africa with limited health facilities and personnel. This study reports on a training programme for CHWs to incorporate RDTs into their management strategy for febrile children in the Democratic Republic of Congo, a tropical African setting ravaged by human conflict.</p> <p>Methods</p> <p>Prospective cohort study, satisfaction questionnaire and decision analysis.</p> <p>Results</p> <p>Twelve CHWs were trained to safely and accurately perform and interpret RDTs, then successfully implemented rapid diagnostic testing in their remote community in a cohort of 357 febrile children. CHWs were uniformly positive in evaluating RDTs for their utility and ease of use. However, high malaria prevalence in this cohort (93% by RDTs, 88% by light microscopy) limited the cost-effectiveness of RDTs compared to presumptive treatment of all febrile children, as evidenced by findings from a simplified decision analysis.</p> <p>Conclusions</p> <p>CHWs can safely and effectively use RDTs in their management of febrile children; however, cost-effectiveness of RDTs is limited in zones of high malaria prevalence.</p

    Accuracy of Transperineal Targeted Prostate Biopsies, Visual Estimation and Image Fusion in Men Needing Repeat Biopsy in the PICTURE Trial

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    PURPOSE: To evaluate detection of clinically significant prostate cancer (csPCa) using MRI-targeted biopsies, and compare visual-estimation to image-fusion targeting, in patients requiring repeat prostate biopsies. MATERIALS AND METHODS: Prospective, ethics-committee approved, registered PICTURE trial enrolling 249 consecutive patients (11th/January/2012-29th/January/2014). Men underwent an mpMRI and were blinded to its results. All underwent transperineal template prostate mapping (TTPM) biopsies. In 200 with a lesion, this was preceded by visual-estimation and image-fusion targeted biopsies. For the primary endpoint, csPCa was defined as Gleason >/=4+3 and/or any grade of cancer length >/=6mm. Other definitions of csPCa were also evaluated. RESULTS: Mean (SD) age was 62.6 (7) years, median (IQR) PSA 7.17ng/ml (5.25, 10.09), mean primary lesion size 0.37cc (SD1.52), with mean 4.3 (SD2.3) targeted cores per lesion (visual-estimation and image-fusion combined) and mean 48.7 (SD12.3) TTPM-biopsy cores. TTPM-biopsies detected 97 (48.5%) cases of csPCa and 85 (42.5%) insignificant cancers. Overall, mpMRI-targeted biopsies detected 81 (40.5%) csPCa and 63 (31.5%) insignificant cancers. Eighteen (9%) with csPCa on MRI-targeted biopsies were benign or clinically insignificant on TTPM-biopsy. Thirty-four (17%) had csPCa detected on TTPM-biopsy but not on MRI-targeted biopsies; approximately half of these were present in non-targeted areas. csPCa was found with visual-estimation and image-fusion in 53/169 (31.3%) and 48/169 (28.4%) (McNemar's test, p=0.5322). Visual-estimation missed 23 (13.6%) csPCa detected by image-fusion; image-fusion missed 18 (10.8%) csPCa that visual-estimation detected. CONCLUSIONS: MRI-targeted biopsies are accurate at detection of csPCa and reducing over-diagnosis of insignificant cancers. To maximise detection both visual-estimation and image-fusion targeted biopsies are required

    A pragmatic cluster randomised trial evaluating three implementation interventions

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    Background Implementation research is concerned with bridging the gap between evidence and practice through the study of methods to promote the uptake of research into routine practice. Good quality evidence has been summarised into guideline recommendations to show that peri-operative fasting times could be considerably shorter than patients currently experience. The objective of this trial was to evaluate the effectiveness of three strategies for the implementation of recommendations about peri-operative fasting. Methods A pragmatic cluster randomised trial underpinned by the PARIHS framework was conducted during 2006 to 2009 with a national sample of UK hospitals using time series with mixed methods process evaluation and cost analysis. Hospitals were randomised to one of three interventions: standard dissemination (SD) of a guideline package, SD plus a web-based resource championed by an opinion leader, and SD plus plan-do-study-act (PDSA). The primary outcome was duration of fluid fast prior to induction of anaesthesia. Secondary outcomes included duration of food fast, patients' experiences, and stakeholders' experiences of implementation, including influences. ANOVA was used to test differences over time and interventions. Results Nineteen acute NHS hospitals participated. Across timepoints, 3,505 duration of fasting observations were recorded. No significant effect of the interventions was observed for either fluid or food fasting times. The effect size was 0.33 for the web-based intervention compared to SD alone for the change in fluid fasting and was 0.12 for PDSA compared to SD alone. The process evaluation showed different types of impact, including changes to practices, policies, and attitudes. A rich picture of the implementation challenges emerged, including inter-professional tensions and a lack of clarity for decision-making authority and responsibility. Conclusions This was a large, complex study and one of the first national randomised controlled trials conducted within acute care in implementation research. The evidence base for fasting practice was accepted by those participating in this study and the messages from it simple; however, implementation and practical challenges influenced the interventions' impact. A set of conditions for implementation emerges from the findings of this study, which are presented as theoretically transferable propositions that have international relevance. Trial registration ISRCTN18046709 - Peri-operative Implementation Study Evaluation (POISE

    Measurement of the hadronic photon structure function F_{2}^{γ} at LEP2

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    The hadronic structure function of the photon F_{2}^{γ} (x, Q²) is measured as a function of Bjorken x and of the photon virtuality Q² using deep-inelastic scattering data taken by the OPAL detector at LEP at e⁺e⁻ centre-of-mass energies from 183 to 209 GeV. Previous OPAL measurements of the x dependence of F_{2}^{γ} are extended to an average Q² of 〈Q²〉=780 GeV² using data in the kinematic range 0.15<x<0.98. The Q² evolution of F_{2}^{γ} is studied for 12.1<〈Q²〉<780 GeV² using three ranges of x. As predicted by QCD, the data show positive scaling violations in F_{2}^{γ} with F_{2}^{γ} (Q²)/α = (0.08±0.02⁺⁰·⁰⁵_₀.₀₃) + (0.13±0.01⁺⁰·⁰¹_₀.₀₁) lnQ², where Q² is in GeV², for the central x region 0.10–0.60. Several parameterisations of F_{2}^{γ} are in qualitative agreement with the measurements whereas the quark-parton model prediction fails to describe the data

    Measurement of the charm structure function F_{2,c)^{γ} of the photon at LEP

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    The production of charm quarks is studied in deep-inelastic electron–photon scattering using data recorded by the OPAL detector at LEP at nominal e⁺e⁻ centre-of-mass energies from 183 to 209 GeV. The charm quarks have been identified by full reconstruction of charged D* mesons using their decays into D⁰π with the D⁰ observed in two decay modes with charged particle final states, Kπ and Kπππ. The cross-section σ^{D*} for production of charged D* in the reaction e⁺e⁻→e⁺e⁻D*Χ is measured in a restricted kinematical region using two bins in Bjorken x, 0.00140.1 the perturbative QCD calculation at next-to-leading order agrees perfectly with the measured cross-section. For x<0.1 the measured cross-section is 43.8±14.3±6.3±2.8 pb with a next-to-leading order prediction of 17.0⁺²·⁹_₂.₃ pb

    Knowledge, attitudes, and practice of oncologists and oncology health care providers in promoting physical activity to cancer survivors: An international survey

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    Objective: To investigate knowledge, attitudes and practices of oncologists towards physical 2 activity (PA) in cancer survivors, and the association between oncologists’ own PA behavior 3 and PA promotion. Methods: Oncologists (n=123) completed a survey based on the Theory of 4 Planned Behavior (TPB). Participants reported PA promotion behavior, PA involvement, 5 attitudes, intentions, social norm, Perceived Behavioral Control (PBC), confidence and 6 knowledge of exercise prescription. Structural equation modelling (SEM) evaluated these 7 associations. Results: Less than half of oncologists reported regularly promoting PA to 8 patients (46%), with 20% providing written information and 23% referrals. Only 26% were 9 physically active. TPB SEM pathways explained 54.6% of the variance in PA promotion 10 (CFI=0.905, SRMR=0.040). Social norm was the only significant pathway to intention, but 11 also a significant indirect pathway to PA promotion (p=.007). Confidence to promote PA, 12 PBC and intentions were direct significant pathways to PA promotion (p\u3c.05). Exploratory 13 SEM pathways explained 19.6% of the variance of PA behavior, which in turn explained 14 13.1% Social Norm, 10.7% Attitude, 10.0% Confidence to Recommend and 17.8% PA 15 promotion behavior (CFI=0.921, SRMR=0.076). Instrumental-attitude was a direct significant 16 pathway to PA behavior (p=.001). PA behavior was a direct significant pathway to social 17 norms, attitude, confidence to recommend, and PA promotion (p \u3c 0.05). Conclusions: 18 Oncologists reported a modest ability to promote PA, low PA promotion rates and limited 19 knowledge of exercise prescription. Patient physical activity promotion may be improved 20 through strategies that increase oncologists’ PBC, confidence and their own personal PA 21 participation
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