1,320 research outputs found

    Phylogenetic revision of Backhousieae (Myrtaceae): Neogene divergence, a revised circumscription of Backhousia and two new species

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    Backhousieae is a small tribe of Myrtaceae composed of two genera (Backhousia and Choricarpia) endemic to Australia. Phylogenetic analyses (parsimony, maximum likelihood and Bayesian) were performed on a combined chloroplast (matK, trnH–psbA, trnC–psbM, trnL–F, rps16) and nuclear (internal transcribed spacers) dataset for all nine species of Backhousia, two species of Choricarpia and two undescribed species. Backhousieae is monophyletic; however, Choricarpia is embedded within Backhousia. In all analyses there were four strongly supported clades containing two to four taxa, with no support for relationships among clades, and the relationships of B. bancroftii and B. citriodora remain unresolved. Bayesian relaxed-clock molecular dating indicated that the Backhousieae has been potentially present in rainforest across Australia for more than 50 million years. The current distribution of Backhousia is inferred to be largely due to the contraction of Australian rainforest in the Neogene. New combinations in Backhousia are made for the two species of Choricarpia, and B. gundarara and B. tetraptera are described as new species. B. gundarara is known only from the Kimberley region of Western Australia, widely disjunct from the remaining Backhousia in eastern Queensland and New South Wales, and appears to be a lineage isolated by increasing aridity during the Miocene

    The HIV-associated tuberculosis epidemic--when will we act?

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    Despite policies, strategies, and guidelines, the epidemic of HIV-associated tuberculosis continues to rage, particularly in southern Africa. We focus our attention on the regions with the greatest burden of disease, especially sub-Saharan Africa, and concentrate on prevention of tuberculosis in people with HIV infection, a challenge that has been greatly neglected. We argue for a much more aggressive approach to early diagnosis and treatment of HIV infection in affected communities, and propose urgent assessment of frequent testing for HIV and early start of antiretroviral treatment (ART). This approach should result in short-term and long-term declines in tuberculosis incidence through individual immune reconstitution and reduced HIV transmission. Implementation of the 3Is policy (intensified tuberculosis case finding, infection control, and isoniazid preventive therapy) for prevention of HIV-associated tuberculosis, combined with earlier start of ART, will reduce the burden of tuberculosis in people with HIV infection and provide a safe clinical environment for delivery of ART. Some progress is being made in provision of HIV care to HIV-infected patients with tuberculosis, but too few receive co-trimoxazole prophylaxis and ART. We make practical recommendations about how to improve this situation. Early HIV diagnosis and treatment, the 3Is, and a comprehensive package of HIV care, in association with directly observed therapy, short-course (DOTS) for tuberculosis, form the basis of prevention and control of HIV-associated tuberculosis. This call to action recommends that both HIV and tuberculosis programmes exhort implementation of strategies that are known to be effective, and test innovative strategies that could work. The continuing HIV-associated tuberculosis epidemic needs bold but responsible action, without which the future will simply mirror the past

    Depairing critical current achieved in superconducting thin films with through-thickness arrays of artificial pinning centers

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    Large area arrays of through-thickness nanoscale pores have been milled into superconducting Nb thin films via a process utilizing anodized aluminum oxide thin film templates. These pores act as artificial flux pinning centers, increasing the superconducting critical current, Jc, of the Nb films. By optimizing the process conditions including anodization time, pore size and milling time, Jc values approaching and in some cases matching the Ginzburg-Landau depairing current of 30 MA/cm^2 at 5 K have been achieved - a Jc enhancement over as-deposited films of more than 50 times. In the field dependence of Jc, a matching field corresponding to the areal pore density has also been clearly observed. The effect of back-filling the pores with magnetic material has then been investigated. While back-filling with Co has been successfully achieved, the effect of the magnetic material on Jc has been found to be largely detrimental compared to voids, although a distinct influence of the magnetic material in producing a hysteretic Jc versus applied field behavior has been observed. This behavior has been tested for compatibility with currently proposed models of magnetic pinning and found to be most closely explained by a model describing the magnetic attraction between the flux vortices and the magnetic inclusions.Comment: 9 pages, 10 figure

    Controlled core-to-core photo-polymerisation – fabrication of an optical fibre-based pH sensor

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    The fabrication of fluorescence-based pH sensors, embedded into etched pits of an optical fibre via highly controllable and spatially selective photo-polymerisation is described and the sensors validated.</p

    Correlates of total sedentary time and screen time in 9-11 year-old children around the world : the international study of childhood obesity, lifestyle and the environment

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    Purpose: Previously, studies examining correlates of sedentary behavior have been limited by small sample size, restricted geographic area, and little socio-cultural variability. Further, few studies have examined correlates of total sedentary time (SED) and screen time (ST) in the same population. This study aimed to investigate correlates of SED and ST in children around the world. Methods: The sample included 5,844 children (45.6% boys, mean age = 10.4 years) from study sites in Australia, Brazil, Canada, China, Colombia, Finland, India, Kenya, Portugal, South Africa, the United Kingdom, and the United States. Child- and parent-reported behavioral, household, and neighborhood characteristics and directly measured anthropometric and accelerometer data were obtained. Twenty-one potential correlates of SED and ST were examined using multilevel models, adjusting for sex, age, and highest parental education, with school and study site as random effects. Variables that were moderately associated with SED and/or ST in univariate analyses (p<0.10) were included in the final models. Variables that remained significant in the final models (p<0.05) were considered correlates of SED and/or ST. Results: Children averaged 8.6 hours of daily SED, and 54.2% of children failed to meet ST guidelines. In all study sites, boys reported higher ST, were less likely to meet ST guidelines, and had higher BMI z-scores than girls. In 9 of 12 sites, girls engaged in significantly more SED than boys. Common correlates of higher SED and ST included poor weight status, not meeting physical activity guidelines, and having a TV or a computer in the bedroom. Conclusions: In this global sample many common correlates of SED and ST were identified, some of which are easily modifiable (e.g., removing TV from the bedroom), and others that may require more intense behavioral interventions (e.g., increasing physical activity). Future work should incorporate these findings into the development of culturally meaningful public health messages

    Burkholderia pseudomallei in Unchlorinated Domestic Bore Water, Tropical Northern Australia

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    To determine whether unchlorinated bore water in northern Australia contained Burkholderia pseudomallei organisms, we sampled 55 bores; 18 (33%) were culture positive. Multilocus sequence typing identified 15 sequence types. The B. pseudomallei sequence type from 1 water sample matched a clinical isolate from a resident with melioidosis on the same property

    Superconductor-ferromagnet nanocomposites created by co-deposition of niobium and dysprosium

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    We have created superconductor-ferromagnet composite films in order to test the enhancement of critical current density, Jc, due to magnetic pinning. We co-sputter the type-II superconductor niobium (Nb) and the low-temperature ferromagnet dysprosium (Dy) onto a heated substrate; the immiscibility of the two materials leads to a phase-separated composite of magnetic regions within a superconducting matrix. Over a range of compositions and substrate temperatures, we achieve phase separation on scales from 5 nm to 1 micron. The composite films exhibit simultaneous superconductivity and ferromagnetism. Transport measurements show that while the self-field Jc is reduced in the composites, the in-field Jc is greatly enhanced up to the 3 T saturation field of Dy. In one instance, the phase separation orders into stripes, leading to in-plane anisotropy in Jc.Comment: 7 pages, 7 figures. Matches the version published in SUST: Added one reference and some discussion in Section

    Melioidosis in Birds and Burkholderia pseudomallei Dispersal, Australia

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    To the Editor: Melioidosis is an emerging infectious disease of humans and animals caused by the gram-negative bacterium Burkholderia pseudomallei, which inhabits soil and surface water in the disease-endemic regions of Southeast Asia and northern Australia (1). The aim of this study was to assess the potential for birds to spread B. pseudomallei. Birds are known carriers of various human pathogens, including influenza viruses, West Nile virus, Campylobacter jejuni, and antimicrobial drug&ndash;resistant Escherichia coli (2)
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