1,102 research outputs found

    V-like formations in flocks of artificial birds

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    We consider flocks of artificial birds and study the emergence of V-like formations during flight. We introduce a small set of fully distributed positioning rules to guide the birds' movements and demonstrate, by means of simulations, that they tend to lead to stabilization into several of the well-known V-like formations that have been observed in nature. We also provide quantitative indicators that we believe are closely related to achieving V-like formations, and study their behavior over a large set of independent simulations

    Simulation Learning: Effectiveness and Stressfulness in Medical Student Teaching

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    This article was migrated. The article was not marked as recommended. Introduction: The aims of this study were to assess the effectiveness of different modalities of simulation learning in medical students and the resulting stress response. Methods: Students were randomised into two groups for simulation learning, on the assessment and management of acutely ill patients. Group 1 performed assessments in a static individual format, whilst group 2 performing assessments in a dynamic group format. The stress response was measured by heart rate monitors worn by students, and performance was graded by a final simulator assessment. Results: The stress response did not significantly vary between groups, but there was a significant increase in heart rate in all students during the simulation learning; with a mean increase of 34 beats per minute in group 1 and 38 beats per minute in group 2. Performance in the final simulator assessment was significantly better in group 2, with a mean score of 21.5 points, compared to 16.2 points in group 1. Conclusion: A dynamic group simulation learning strategy is more effective in teaching medical students than simulations performed individually. Simulation learning, however; results in a significant stress response in all students, which must be carefully managed when delivering this type of learning.</ns4:p

    Temperature Dependence of Low Cycle Fatigue Behavior in AZ31 Magnesium Alloy

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    In situ neutron diffraction has been used to investigate the deformation behaviour of extruded magnesium at room temperature, -100. Ā°C and 150. Ā°C. Significant differences in the active twinning/slip systems, attributed to the strong crystallographic texture and temperature dependence, were observed. Twining is the dominant deformation mode during the cyclic loading at room temperature and at cryogenic temperature. In contrast, at high temperature, additional slip planes were activated and reduction of twinning activities was observed and the deformation mode is slip-dominated

    Development and testing of the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS) cm and mm wavelength occultation instrument

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    We present initial results from testing a new remote sensing system called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). ATOMMS is designed as a satellite-to-satellite occultation system for monitoring climate. We are developing the prototype instrument for an aircraft to aircraft occultation demonstration. Here we focus on field testing of the ATOMMS instrument, in particular the remote sensing of water by measuring the attenuation caused by the 22 GHz and 183 GHz water absorption lines. Our measurements of the 183 GHz line spectrum along an 820 m path revealed that the AM 6.2 spectroscopic model provdes a much better match to the observed spectrum than the MPM93 model. These comparisons also indicate that errors in the ATOMMS amplitude measurements are about 0.3%. Pressure sensitivity bodes well for ATOMMS as a climate instrument. Comparisons with a hygrometer revealed consistency at the 0.05 mb level, which is about 1% of the absolute humidity. Initial measurements of absorption by the 22 GHz line made along a 5.4 km path between two mountaintops captured a large increase in water vapor similar to that measured by several nearby hygrometers. A storm passage between the two instruments yielded our first measurements of extinction by rain and cloud droplets. Comparisons of ATOMMS 1.5 mm opacity measurements with measured visible opacity and backscatter from a weather radar revealed features simultaneously evident in all three datasets confirming the ATOMMS measurements. The combined ATOMMS, radar and visible information revealed the evolution of rain and cloud amounts along the signal path during the passage of the storm. The derived average cloud water content reached typical continental cloud amounts. These results demonstrated a significant portion of the information content of ATOMMS and its ability to penetrate through clouds and rain which is critical to its all-weather, climate monitoring capability

    Using Technology for Community Engagement: Four Key Web-Based Platforms for Adoption in Extension

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    Extension professionals engage with communities to present programming, find solutions, and disseminate research-based knowledge. While traditional means of communication and face-to-face meetings are still important, the COVID-19 pandemic shifted the ways these professionals connect to their communities. Web-based platforms can provide unique, alternative ways to engage communities in programs, evaluations, and information sharing. Our team of Extension professionals share platforms that create engaged communities by meeting virtual demands

    Inhibition of Dermatophyte Fungi by Australian Jarrah Honey.

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    Superficial dermatophyte infections, commonly known as tineas, are the most prevalent fungal ailment and are increasing in incidence, leading to an interest in alternative treatments. Many floral honeys possess antimicrobial activity due to high sugar, low pH, and the production of hydrogen peroxide (H2O2) from the activity of the bee-derived enzyme glucose oxidase. Australian jarrah (Eucalyptus marginata) honey produces particularly high levels of H2O2 and has been found to be potently antifungal. This study characterized the activity of jarrah honey on fungal dermatophyte species. Jarrah honey inhibited dermatophytes with minimum inhibitory concentrations (MICs) of 1.5-3.5% (w/v), which increased to ā‰„25% (w/v) when catalase was added. Microscopic analysis found jarrah honey inhibited the germination of Trichophyton rubrum conidia and scanning electron microscopy of mature T. rubrum hyphae after honey treatment revealed bulging and collapsed regions. When treated hyphae were stained using REDOX fluorophores these did not detect any internal oxidative stress, suggesting jarrah honey acts largely on the hyphal surface. Although H2O2 appears critical for the antifungal activity of jarrah honey and its action on fungal cells, these effects persisted when H2O2 was eliminated and could not be replicated using synthetic honey spiked with H2O2, indicating jarrah honey contains agents that augment antifungal activity

    Rapid neuroinflammatory changes in human acute intracerebral hemorrhage

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    Objective Spontaneous intracerebral hemorrhage (ICH) is the commonest form of hemorrhagic stroke and is associated with a poor prognosis. Neurosurgical removal of intracerebral hematoma has limited benefit and no pharmacotherapies are available. In acute ICH, primary tissue damage is followed by secondary pathology, where the cellular and neuroinflammatory changes are poorly understood. Methods We studied histological changes in postmortem tissue from a cohort of spontaneous supraā€tentorial primary ICH cases (n = 27) with survival of 1ā€“12 days, compared to a matched control group (n = 16) examined in corresponding regions. Hematoxylinā€“eosin and microglial (Iba1) immunolabelled sections were assessed at 0ā€“2, 3ā€“5, and 7ā€“12 days postā€ICH. Results Periā€hematoma, the observed ICHā€related changes include edema, tissue neutrophils and macrophages from day 1. Ischemic neurons and swollen endothelial cells were common at day 1 and universal after day 5, as were intramural erythrocytes within small vessel walls. Activated microglia were evident at day 1 postā€ICH. There was a significant increase in Iba1 positive area fraction at 0ā€“2 (threefold), 3ā€“5 (fourfold), and 7ā€“12 days post ICH (ninefold) relative to controls. Giant microglia were detected periā€hematoma from day 5 and consistently 7ā€“12 days postā€ICH. Interpretation Our data indicate that neuroinflammatory processes commence from day 1 postā€ICH with changing microglial size and morphology following ICH and up to day 12. From day 5 some microglia exhibit a novel multiply nucleated morphology, which may be related to changing phagocytic function. Understanding the time course of neuroinflammatory changes, postā€ICH may reveal novel targets for therapy and brain restoration

    BRIDGE: An Open-Label Phase II Trial Evaluating the Safety of Bevacizumab + Carboplatin/Paclitaxel as First-Line Treatment for Patients with Advanced, Previously Untreated, Squamous Non-small Cell Lung Cancer

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    Background:Patients with predominantly squamous non-small cell lung cancer (NSCLC) have been generally excluded from studies of bevacizumab treatment, because squamous histology was identified as a possible risk factor for severe (grade ā‰„3) pulmonary hemorrhage (PH) in a phase II study. BRIDGE was designed to determine whether delaying initiation of bevacizumab treatment and selecting patients without baseline risk factors for PH would lower the incidence of severe PH among patients with squamous NSCLC.Methods:Patients in this open-label, single-arm study were treated with carboplatin/paclitaxel for two cycles, followed by carboplatin/paclitaxel and bevacizumab in cycles 3 to 6, followed by bevacizumab until progression or unacceptable toxicity. Eligible patients had stage IIIb, stage IV, or recurrent squamous NSCLC. The primary end point was incidence of grade ā‰„3 PH.Results:Grade ā‰„3 PH occurred in 1 of 31 patients who received ā‰„1 dose of bevacizumab: estimated incidence was 3.2% (90% confidence interval 0.3ā€“13.5%). The patient experienced grade 3 PH, discontinued from the study, then experienced grade 4 PH 10 days later, and died of progressive disease. No other serious bleeding events occurred. Nine patients (29.0%) experienced grade 3 adverse events, including five with hypertension; five patients experienced grade 4 adverse events (dyspnea, PH, basal ganglia infarction, cerebral ischemia, and pain). Median progression-free survival was 6.2 months (95% confidence interval 5.32ā€“7.62 months).Conclusions:The incidence of grade ā‰„3 PH was 3.2% (one patient). No new safety signals were identified. Although the rate of PH was low, the number of patients in this study was also low. Treatment of squamous NSCLC with bevacizumab should be considered experimental
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