4,471 research outputs found

    Epidemiological Impact of Tenofovir Gel on the HIV Epidemic in South Africa

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    BACKGROUND: Tenofovir gel, an antiretroviral-based vaginal microbicide, reduced HIV acquisition by 39% in women in a recent randomized controlled clinical trial in South Africa. METHODS: To inform policy, we used a dynamical model of HIV transmission, calibrated to the epidemic in South Africa, to determine the population-level impact of this microbicide on HIV incidence, prevalence, and deaths and to evaluate its cost-effectiveness. RESULTS: If women use tenofovir gel in 80% or more of sexual encounters (high coverage), it could avert 2.33 (0.12 to 4.63) million new infections and save 1.30 (0.07 to 2.42) million lives and if used in 25% of sexual encounters (low coverage), it could avert 0.50 (0.04 to 0.77) million new infections and save 0.29 (0.02 to 0.44) million deaths, over the next 20 years. At US 0.50perapplication,thecostperinfectionavertedatlowcoverageisUS0.50 per application, the cost per infection averted at low coverage is US 2392 (US 562toUS562 to US 4222) and the cost per disability-adjusted life year saved is US 104(US104 (US 27 to US $181); at high coverage the costs are about 30% less. CONCLUSIONS: Over 20 years, the use of tenofovir gel in South Africa could avert up to 2 million new infections and 1 million AIDS deaths. Even with low rates of gel use, it is highly cost-effective and compares favorably with other control methods. This female-controlled prevention method could have a significant impact on the epidemic of HIV in South Africa. Programs should aim to achieve gel use in more than 25% of sexual encounters to significantly alter the course of the epidemic

    Absence of the Filarial Endosymbiont Wolbachia in Seal Heartworm (Acanthocheilonema spirocauda) but Evidence of Ancient Lateral Gene Transfer

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    The symbiotic relationship of Wolbachia spp. was first observed in insects and subsequently in many parasitic filarial nematodes. This bacterium is believed to provide metabolic and developmental assistance to filarial parasitic nematodes, although the exact nature of this relationship remains to be fully elucidated. While Wolbachia is present in most filarial nematodes in the familyOnchocercidae, it is absent in several disparate species such as the human parasite Loa loa. All tested members of the genusAcanthocheilonema, such as Acanthocheilonema viteae, have been shown to lack Wolbachia. Consistent with this, we show thatWolbachia is absent from the seal heartworm (Acanthocheilonema spirocauda), but lateral gene transfer (LGT) of DNA sequences between Wolbachia and A. spirocauda has occurred, indicating a past evolutionary association. Seal heartworm is an important pathogen of phocid seals and understanding its basic biology is essential for conservation of the host. The findings presented here may allow for the development of future treatments or diagnostics for the disease and also aid in clarification of the complicated nematode–Wolbachia relationship

    Effect of Native American ancestry on iron-related phenotypes of Alabama hemochromatosis probands with HFE C282Y homozygosity

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    BACKGROUND: In age-matched cohorts of screening study participants recruited from primary care clinics, mean serum transferrin saturation values were significantly lower and mean serum ferritin concentrations were significantly higher in Native Americans than in whites. Twenty-eight percent of 80 Alabama white hemochromatosis probands with HFE C282Y homozygosity previously reported having Native American ancestry, but the possible effect of this ancestry on hemochromatosis phenotypes was unknown. METHODS: We compiled observations in these 80 probands and used univariate and multivariate methods to analyze associations of age, sex, Native American ancestry (as a dichotomous variable), report of ethanol consumption (as a dichotomous variable), percentage transferrin saturation and log(e )serum ferritin concentration at diagnosis, quantities of iron removed by phlebotomy to achieve iron depletion, and quantities of excess iron removed by phlebotomy. RESULTS: In a univariate analysis in which probands were grouped by sex, there were no significant differences in reports of ethanol consumption, transferrin saturation, log(e )serum ferritin concentration, quantities of iron removed to achieve iron depletion, and quantities of excess iron removed by phlebotomy in probands who reported Native American ancestry than in those who did not. In multivariate analyses, transferrin saturation (as a dependent variable) was not significantly associated with any of the available variables, including reports of Native American ancestry and ethanol consumption. The independent variable quantities of excess iron removed by phlebotomy was significantly associated with log(e )serum ferritin used as a dependent variable (p < 0.0001), but not with reports of Native American ancestry or reports of ethanol consumption. Log(e )serum ferritin was the only independent variable significantly associated with quantities of excess iron removed by phlebotomy used as a dependent variable (p < 0.0001) (p < 0.0001; ANOVA of regression). CONCLUSION: We conclude that the iron-related phenotypes of hemochromatosis probands with HFE C282Y homozygosity are similar in those with and without Native American ancestry reports

    Predicting Neutron Production from Cosmic-ray Muons

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    Fast neutrons from cosmic-ray muons are an important background to underground low energy experiments. The estimate of such background is often hampered by the difficulty of measuring and calculating neutron production with sufficient accuracy. Indeed substantial disagreement exists between the different analytical calculations performed so far, while data reported by different experiments is not always consistent. We discuss a new unified approach to estimate the neutron yield, the energy spectrum, the multiplicity and the angular distribution from cosmic muons using the Monte Carlo simulation package FLUKA and show that it gives a good description of most of the existing measurements once the appropriate corrections have been applied.Comment: 8 pages, 7 figure

    Literacy practices of primary education children in Andalusia (Spain): a family-based perspective

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    Primary school children develop literacy practices in various domains and situations in everyday life. This study focused on the analysis of literacy practices of children aged 8–12 years from the perspec- tive of their families. 1,843 families participated in the non-experimental explanatory study. The children in these families speak Spanish as a first language and are schooled in this language. The instrument used was a self-report questionnaire about children’s home-literacy practices. The data obtained were analysed using categorical principal components analysis (CATPCA) and analysis of variance (ANOVA). The results show the complex relationship between literacy practices developed by children in the domains of home and school and the limited development of a literacy-promoting ‘third space’. In conclusion, the families in our study had limited awareness of their role as literacy- promoting agents and thought of literacy learning as restricted to formal or academic spaces

    Whole genome sequencing increases molecular diagnostic yield compared with current diagnostic testing for inherited retinal disease

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    Abstract not availableJamie M. Ellingford, Stephanie Barton, Sanjeev Bhaskar, Simon G. Williams, Panagiotis I. Sergouniotis, James O, Sullivan, Janine A. Lamb, Rahat Perveen, Georgina Hall, William G. Newman, Paul N. Bishop, Stephen A. Roberts, Rick Leach, Rick Tearle, Stuart Bayliss, Simon C. Ramsden, Andrea H. Nemeth, Graeme C.M. Blac

    Neutron production by cosmic-ray muons at shallow depth

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    The yield of neutrons produced by cosmic ray muons at a shallow depth of 32 meters of water equivalent has been measured. The Palo Verde neutrino detector, containing 11.3 tons of Gd loaded liquid scintillator and 3.5 tons of acrylic served as a target. The rate of one and two neutron captures was determined. Modeling the neutron capture efficiency allowed us to deduce the total yield of neutrons Ytot=(3.60±0.09±0.31)×105 Y_{tot} = (3.60 \pm 0.09 \pm 0.31) \times 10^{-5} neutrons per muon and g/cm2^2. This yield is consistent with previous measurements at similar depths.Comment: 12 pages, 3 figure

    The giant lobes of Centaurus A observed at 118 MHz with the Murchison Widefield Array

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    We present new wide-field observations of Centaurus A (Cen A) and the surrounding region at 118MHz with the Murchison Widefield Array (MWA) 32-tile prototype, with which we investigate the spectral-index distribution of Cen A's giant radio lobes.We compa
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