469 research outputs found

    Self-awareness of driving impairment in patients with cataract or glaucoma

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    This study compared the driving performance of individuals with the eye diseases cataracts or glaucoma with age-matched controls, as well as the individual’s own perceptions of driving. Participants included drivers over the age of 50 years who had been diagnosed with glaucoma (n=29) or cataracts (n=33) and a control group with no ocular pathology (n=13). Driving performance was measured on a closed road circuit using a range of standardised measures of vehicle control and hazard recognition and avoidance, while visual performance was measured with a battery of tests including visual acuity, contrast sensitivity and visual fields. Perceptions of vision and driving were assessed using the Activities of Daily Vision Scale, Driver Behaviour Questionnaire and a driving exposure questionnaire. Driving performance was significantly poorer (p<0.05) for each of the ocular disease groups compared to the control group. Impaired contrast sensitivity and the higher disease severity scores (for the glaucoma group only) correlated most strongly with poorer driving performance. While participants with cataracts rated their vision significantly more poorly than those in the glaucoma and control groups, there were no significant differences between the participant groups rating of their own driving performance. These findings suggest that there is no direct relationship between self-rated driving ability and actual vision and driving performance. This has serious road safety implications

    PIV Study of the Vortex Wake behind a Translationally Oscillating Cylinder in a Quiescent Fluid

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    The near wake produced by a circular cylinder oscillating translationally in a quiescent fluid or, alternatively, by oscillatory flow past a stationary cylinder at low Keulegan-Carpenter (KC) and Stokes (b) numbers has been investigated using Particle Image Velocimetry. All but one of the two- and three-dimensional regimes of the Tatsuno & Bearman [11] map were investigated. The findings are successfully compared with previous experimental observations and numerical simulations. Twodimensional Particle Image Velocimetry results of regime B show how the symmetrical pattern of vortices around the cylinder becomes three-dimensional. Additionally, the instantaneous results of regime E confirm that there is an intermittent change in the direction of the V-shaped vortices around the cylinder

    Assembly and force measurement with SPM-like probes in holographic optical tweezers

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    We report a high fidelity tomographic reconstruction of the quantum state of photon pairs generated by parametric down-conversion with orbital angular momentum (OAM) entanglement. Our tomography method allows us to estimate an upper and lower bound for the entanglement between the down-converted photons. We investigate the two-dimensional state subspace defined by the OAM states ±ℓ and superpositions thereof, with ℓ=1, 2, ..., 30. We find that the reconstructed density matrix, even for OAMs up to around ℓ=20, is close to that of a maximally entangled Bell state with a fidelity in the range between F=0.979 and F=0.814. This demonstrates that, although the single count-rate diminishes with increasing ℓ, entanglement persists in a large dimensional state space

    Safety of guidewire-based measurement of fractional flow reserve and the index of microvascular resistance using intravenous adenosine in patients with acute or recent myocardial infarction

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    Aims: Coronary guidewire-based diagnostic assessments with hyperemia may cause iatrogenic complications. We assessed the safety of guidewire-based measurement of coronary physiology, using intravenous adenosine, in patients with an acute coronary syndrome. Methods: We prospectively enrolled invasively managed STEMI and NSTEMI patients in two simultaneously conducted studies in 6 centers (NCT01764334; NCT02072850). All of the participants underwent a diagnostic coronary guidewire study using intravenous adenosine (140 μg/kg/min) infusion for 1–2 min. The patients were prospectively assessed for the occurrence of serious adverse events (SAEs) and symptoms and invasively measured hemodynamics were also recorded. Results: 648 patients (n = 298 STEMI patients in 1 hospital; mean time to reperfusion 253 min; n = 350 NSTEMI in 6 hospitals; median time to angiography from index chest pain episode 3 (2, 5) days) were included between March 2011 and May 2013. Two NSTEMI patients (0.03% overall) experienced a coronary dissection related to the guidewire. No guidewire dissections occurred in the STEMI patients. Chest symptoms were reported in the majority (86%) of patient's symptoms during the adenosine infusion. No serious adverse events occurred during infusion of adenosine and all of the symptoms resolved after the infusion ceased. Conclusions: In this multicenter analysis, guidewire-based measurement of FFR and IMR using intravenous adenosine was safe in patients following STEMI or NSTEMI. Self-limiting symptoms were common but not associated with serious adverse events. Finally, coronary dissection in STEMI and NSTEMI patients was noted to be a rare phenomenon

    Microwave assisted heterogeneous catalysis: effects of varying oxygen concentrations on the oxidative coupling of methane

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    The oxidative coupling of methane was investigated over alumina supported La2O3/CeO2 catalysts under microwave dielectric heating conditions at different oxygen concentrations. It was observed that, at a given temperature using microwave heating, selectivities for both ethane and ethylene were notably higher when oxygen was absent than that in oxygen/methane mixtures. The differences were attributed to the localised heating of microwave radiation resulting in temperature inhomogeneity in the catalyst bed. A simplified model was used to estimate the temperature inhomogeneity; the temperature at the centre of the catalyst bed was 85 °C greater than that at the periphery when the catalyst was heated by microwaves in a gas mixture with an oxygen concentration of 12.5% (v/v), and the temperature difference was estimated to be 168 °C in the absence of oxygen

    Reversibility in nonequilibrium trajectories of an optically trapped particle

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    The measure of irreversibility as the dissipation function that serves as the quantitative argument in the fluctuation theorem (FT) was investigated. The FT describes the system's thermodynamic irreversibility developed in time from a completely thermodynamically reversibble system at short times to a thermodynamically irreversible one at infinitely long times. It was observed that the ensemble average of ωt was positive definite irrespective of the system for which it was constructed. It was found that the different expressions for ωt can arise in stochastic and deterministic systems

    The growth and development of pearl millet as affected by plant population

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    Pearlmillet (Pennisetum americanum (L.) Leeke) was grown at ICRISAT, Hyderabad, India at 20 densities ranging from 50 000 to 400 000 plants ha−1 using a Nelder fan design. Studies were made on the effect of population on the distribution of plant dry weight, leaf area, grain yield and yield components throughout the season. The first effect of increasing population was evident at panicle initiation (<6% final dry weight produced) where dry weight accumulation in the main axis was unaffected but that in the tillers was reduced. Subsequently, the increased plant population resulted in reductions of 77% in total weight per plant, 66% in leaf area per plant and 59% in tiller number per plant at 50% anthesis. Thedevelopmentof green leaf area per plant followed the same trend over the range of populations, so that leaf area index ranged with increasing population from 2.9 to 6.7 at 50% anthesis; severe leaf senescence occurred in the latter part of grain filling. As population increased, thedevelopmentof tillers terminated earlier in thegrowthofthe plant, resulting in a reduced tiller survival rate and therefore reduced productive head numbers per plant. Grain yield per plant declined owing to the reduced head numbers and also to lower seed numbers per head. Seed size remained largely unchanged. Population influenced plant yield chiefly through the highly responsive yield fraction of tillers, asthe yield ofthe main axis was relatively stable. Grain yield ha−1 increased to a maximum at 150 000 plants ha−1, which was maintained through to 400 000 plants ha−1 due to the large degree of plasticity in productive tiller number per plan

    The journey to R4D: An institutional history of an Australian initiative on food Security in Africa

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    The Role of Glutathione S-Transferase GliG in Gliotoxin Biosynthesis in Aspergillus fumigatus

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    Gliotoxin, a redox-active metabolite, is produced by the opportunistic fungal pathogen Aspergillus fumigatus, and its biosynthesis is directed by the gli gene cluster. Knowledge of the biosynthetic pathway to gliotoxin, which contains a disulfide bridge of unknown origin, is limited, although L-Phe and L-Ser are known biosynthetic precursors. Deletion of gliG from the gli cluster, herein functionally confirmed as a glutathione S-transferase, results in abrogation of gliotoxin biosynthesis and accumulation of 6-benzyl-6-hydroxy-1-methoxy-3-methylenepiperazine- 2,5-dione. This putative shunt metabolite from the gliotoxin biosynthetic pathway contains an intriguing hydroxyl group at C-6, consistent with a gliotoxin biosynthetic pathway involving thiolation via addition of the glutathione thiol group to a reactive acyl imine intermediate. Complementation of gliG restored gliotoxin production and, unlike gliT, gliG was found not to be involved in fungal self-protection against gliotoxin
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