810 research outputs found

    Approximate inverse systems of uniform spaces and an application of inverse systems

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    summary:The fundamental properties of approximate inverse systems of uniform spaces are established. The limit space of an approximate inverse sequence of complete metric spaces is the limit of an inverse sequence of some of these spaces. This has an application to the dimension of the limit space of an approximate inverse system. A topologically complete space with dimn\operatorname{dim} \leq n is the limit of an approximate inverse system of metric polyhedra of dimn\operatorname{dim} \leq n. A completely metrizable separable space with dimn\operatorname{dim} \leq n is the limit of an inverse sequence of locally finite polyhedra of dimn\operatorname{dim} \leq n. Finally, a new proof is derived of the important equality dim=Ind\operatorname{dim} = \operatorname{Ind} for metric spaces

    Second-line antiretroviral therapy in a workplace and community-based treatment programme in South Africa: determinants of virological outcome.

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    : Background: As antiretroviral treatment (ART) programmes in resource-limited settings mature, more patients are experiencing virological failure. Without resistance testing, deciding who should switch to second-line ART can be difficult. The consequences for second-line outcomes are unclear. In a workplace- and community-based multi-site programme, with 6-monthly virological monitoring, we describe outcomes and predictors of viral suppression on second-line, protease inhibitor-based ART.Methods: We used prospectively collected clinic data from patients commencing first-line ART between 1/1/03 and 31/12/08 to construct a study cohort of patients switched to second-line ART in the presence of a viral load (VL) ?400 copies/ml. Predictors of VL<400 copies/ml within 15 months of switch were assessed using modified Poisson regression to estimate risk ratios.Results: 205 workplace patients (91.7% male; median age 43 yrs) and 212 community patients (38.7% male; median age 36 yrs) switched regimens. At switch compared to community patients, workplace patients had a longer duration of viraemia, higher VL, lower CD4 count, and higher reported non-adherence on first-line ART. Non-adherence was the reported reason for switching in a higher proportion of workplace patients. Following switch, 48.3% (workplace) and 72.0% (community) achieved VL<400, with non-adherence (17.9% vs. 1.4%) and virological rebound (35.6% vs. 13.2% with available measures) reported more commonly in the workplace programme. In adjusted analysis of the workplace programme, lower switch VL and younger age were associated with VL<400. In the community programme, shorter duration of viraemia, higher CD4 count and transfers into programme on ART were associated with VL<400.Conclusion: High levels of viral suppression on second-line ART can be, but are not always, achieved in multi-site treatment programmes with both individual- and programme-level factors influencing outcomes. Strategies to support both healthcare workers and patients during this switch period need to be evaluated; sub-optimal adherence, particularly in the workplace programme must be addressed

    Observation of a Triangular to Square Flux Lattice Phase Transition in YBCO

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    We have used the technique of small-angle neutron scattering to observe magnetic flux lines directly in an YBCO single crystal at fields higher than previously reported. For field directions close to perpendicular to the CuO2 planes, we find that the flux lattice structure changes smoothly from a distorted triangular co-ordination to nearly perfectly square as the magnetic induction approaches 11 T. The orientation of the square flux lattice is as expected from recent d-wave theories, but is 45 deg from that recently observed in LSCO

    The effects of dietary hesperidin and naringin supplementation on lamb performance and meat characteristics

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    An experiment was conducted to examine the effects of supplementing feed with hesperidin or naringin, bioflavonoids that are abundant and inexpensive by-products of citrus cultivation, on lambs’ growth performance, carcass and meat characteristics. Fourty-four male Chios lambs were randomly assigned to 4 groups. One of the groups served as control (C) and was given a basal diet, whereas the other 3 groups were given the same diet further supplemented with hesperidin at 2500 mg (H), or naringin at 2500 mg (N), or α-tocopheryl acetate at 200 mg (E) per kg feed. At the end of the experiment (35th day), lambs were fasted, weighed and slaughtered. After overnight chilling, samples of longissimus thoracis muscle were taken and were used for meat quality evaluation. No significant differences were observed in final body weight, body weight gain and edible organ weights among the four experimental groups. pH, colour parameters (L, a*, b*), water holding capacity and shear force value of longissimus thoracis muscle were also not significantly influenced by the dietary treatments. Measurement of lipid oxidation values showed that hesperidin or naringin supplementation positively influenced meat antioxidant properties during the refrigerated storage at 4°C for up to 8 days, however to a lesser extent compared to α-tocopheryl acetate. Nowadays, there is a strong interest in isolating antioxidants from natural sources and using them in animal nutrition with the intention to minimize lipid oxidation in meat products. According to the findings of the present study, flavonoids appeared as a great alternative, since they resulted in an improvement of meat antioxidant capacity leading to a prolongation of its shelf-life and an increase of its acceptability in the market

    Inter-observer agreement of canine and feline paroxysmal event semiology and classification by veterinary neurology specialists and non-specialists

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    Background: Advances in mobile technology mean vets are now commonly presented with videos of paroxysmal events by clients, but the consistency of the interpretation of these videos has not been investigated. The objective of this study was to investigate the level of agreement between vets (both neurology specialists and non-specialists) on the description and classification of videos depicting paroxysmal events, without knowing any results of diagnostic workup. An online questionnaire study was conducted, where participants watched 100 videos of dogs and cats exhibiting paroxysmal events and answered questions regarding: epileptic seizure presence (yes/ no), seizure type, consciousness status, and the presence of motor, autonomic and neurobehavioural signs. Agreement statistics (percentage agreement and kappa) calculated for each variable, with prevalence indices calculated to aid their interpretation. Results: Only a fair level of agreement (kappa = 0.40) was found for epileptic seizure presence. Overall agreement of seizure type was moderate (kappa = 0.44), with primary generalised seizures showing the highest level of agreement (kappa = 0.60), and focal the lowest (kappa = 0.31). Fair agreement was found for consciousness status and the presence of autonomic signs (kappa = 0.21-0.40), but poor agreement for neurobehavioral signs (kappa = 0.16). Agreement for motor signs ranged from poor (kappa = <= 0.20) to moderate (kappa = 0.41-0.60). Differences between specialists and non-specialists were identified. Conclusions: The relatively low levels of agreement described here highlight the need for further discussions between neurology experts regarding classifying and describing epileptic seizures, and additional training of non-specialists to facilitate accurate diagnosis. There is a need for diagnostic tools (e.g. electroencephalogram) able to differentiate between epileptic and non-epileptic paroxysms

    Muons as Local Probes of Three-body Correlations in the Mixed State of Type-II Superconductors

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    The vortex glass state formed by magnetic flux lines in a type-II superconductor is shown to possess non-trivial three-body correlations. While such correlations are usually difficult to measure in glassy systems, the magnetic fields associated with the flux vortices allow us to probe these via muon-spin rotation measurements of the local field distribution. We show via numerical simulations and analytic calculations that these observations provide detailed microscopic insight into the local order of the vortex glass and more generally validate a theoretical framework for correlations in glassy systems.Comment: 4+ pages, high-quality figures available on reques

    Direct observation of the flux-line vortex glass phase in a type II superconductor

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    The order of the vortex state in La_{1.9} Sr_{0.1} CuO_{4} is probed using muon spin rotation and small-angle neutron scattering. A transition from a Bragg glass to a vortex glass is observed, where the latter is composed of disordered vortex lines. In the vicinity of the transition the microscopic behavior reflects a delicate interplay of thermally-induced and pinning-induced disorder.Comment: 14 pages, 4 colour figures include
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