2,672 research outputs found

    Can local communities 'sustain' HIV/AIDS programmes? A South African example

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    Globally, there is a renewed interest in building the local sustainability of HIV/AIDS programmes to ensure that once funders withdraw, local communities can sustain programmes. While the ‘local sustainability assumption’ is widespread, little research has assessed this. In this article, we assess the sustainability of the Entabeni Project, a community-based intervention that sought to build women's local leadership and capacity to respond to HIV/AIDS through a group of volunteer carers, 3 years after external support was withdrawn. Overall, the sustainability of the Entabeni Project was limited. The wider social and political context undermined volunteer carers' sense that they could affect change, with little external support for them from government and NGOs, who struggled to engage with local community organizations. At the community level, some church leaders and community members recognized the important role of health volunteers, many continued to devalue the work of the carers, especially once there was no external organization to support and validate their work. Within the health volunteer group, despite extensive efforts to change dynamics, it remained dominated by a local male leader who denied others active participation while lacking the skills to meaningfully lead the project. Our case study suggests that the local-sustainability assumption is wishful thinking. Small-scale local projects are unlikely to be able to challenge the broader social and political dynamics hindering their sustainability without meaningful external support

    All-Optical Switching with Transverse Optical Patterns

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    We demonstrate an all-optical switch that operates at ultra-low-light levels and exhibits several features necessary for use in optical switching networks. An input switching beam, wavelength λ\lambda, with an energy density of 10210^{-2} photons per optical cross section [σ=λ2/(2π)\sigma=\lambda^2/(2\pi)] changes the orientation of a two-spot pattern generated via parametric instability in warm rubidium vapor. The instability is induced with less than 1 mW of total pump power and generates several μ\muWs of output light. The switch is cascadable: the device output is capable of driving multiple inputs, and exhibits transistor-like signal-level restoration with both saturated and intermediate response regimes. Additionally, the system requires an input power proportional to the inverse of the response time, which suggests thermal dissipation does not necessarily limit the practicality of optical logic devices

    Prevalence of liver fluke (Fasciola hepatica) in wild Red Deer (Cervus elaphus): coproantigen ELISA is a practicable alternative to faecal egg counting for surveillance in remote populations

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    Red deer (Cervus elaphus) are hosts of liver fluke (Fasciola hepatica); yet, prevalence is rarely quantified in wild populations. Testing fresh samples from remote regions by faecal examination (FE) can be logistically challenging; hence, we appraise frozen storage and the use of a coproantigen ELISA (cELISA) for F. hepatica surveillance. We also present cELISA surveillance data for red deer from the Highlands of Scotland. Diagnoses in faecal samples (207 frozen, 146 fresh) were compared using a cELISA and by FE. For each storage method (frozen or fresh), agreement between the two diagnostics was estimated at individual and population levels, where population prevalence was stratified into cohorts (e.g., by sampling location). To approximate sensitivity and specificity, 65 post-slaughter whole liver examinations were used as a reference. At the individual level, FE and cELISA diagnoses agreed moderately (κfrozen = 0.46; κfresh = 0.51), a likely reflection of their underlying principles. At the population level, FE and cELISA cohort prevalence correlated strongly (Pearson’s R = 0.89, p < 0.0001), reflecting good agreement on relative differences between cohort prevalence. In frozen samples, prevalence by cELISA exceeded FE overall (42.8% vs. 25.8%) and in 9/12 cohorts, alluding to differences in sensitivity; though, in fresh samples, no significant difference was found. In 959 deer tested by cELISA across the Scottish Highlands, infection prevalence ranged from 9.6% to 53% by sampling location. We highlight two key advantages of cELISA over FE: i) the ability to store samples long term (frozen) without apparent loss in diagnostic power; and ii) reduced labour and the ability to process large batches. Further evaluation of cELISA sensitivity in red deer, where a range of fluke burdens can be obtained, is desirable. In the interim, the cELISA is a practicable diagnostic for F. hepatica surveillance in red deer, and its application here has revealed considerable geographic, temporal, sex and age related differences in F. hepatica prevalence in wild Scottish Highland red deer

    Matter-wave bistability in coupled atom-molecule quantum gases

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    We study the matter-wave bistability in coupled atom-molecule quantum gases, in which heteronuclear molecules are created via an interspecies Feshbach resonance involving either two-species Bose or two-species Fermi atoms at zero temperature. We show that the resonant two-channel Bose model is equivalent to the nondegenerate parametric down-conversion in quantum optics, while the corresponding Fermi model can be mapped to a quantum optics model that describes a single-mode laser field interacting with an ensemble of inhomogeneously broadened two-level atoms. Using these analogy and the fact that both models are subject to the Kerr nonlinearity due to the two-body s-wave collisions, we show that under proper conditions, the population in the molecular state in both models can be made to change with the Feshbach detuning in a bistable fashion.Comment: 6 pages, 5 figure

    VCU-UNITE: Identifying Recognition Mechanisms for University-Community Engagement

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    The aims of the project were to determine what process would be appropriate to recognize significant contributions of university and community partners to joint community engagement projects. Our view was that several different award ceremonies exist in VCU, none of which are well attended and suggesting that this form of recognition may not be a high priority for participants. Thus, we sought to determine the awareness and extent of involvement of VCU faculty, staff and students in community engagement projects, and to find out what format of recognition process would be appealing to both university and community participants. We gathered this information through surveys and focus groups, analyzed the data and determined that university and community partners had differing views on what types of recognition would be desirous. Next, we designed a web portal through which nominations could be made by members of the university and by the community. We propose a streamlined nomination and online review process, leading to a quarterly award consisting of a letter of thanks from the Division of Community Engagement, and a photograph and narrative placed on the VCU website. Recipients of quarterly awards would automatically compete for an annual award, such as P&T credit or additional community leave time (university), or a scholarship, a plaque, or recognition at a VCU event (community)

    Magnetic frustration and spontaneous rotational symmetry breaking in PdCrO2

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    In the triangular layered magnet PdCrO2 the intralayer magnetic interactions are strong, however the lattice structure frustrates interlayer interactions. In spite of this, long-range, 120^\circ antiferromagnetic order condenses at TN=38T_N = 38~K. We show here through neutron scattering measurements under in-plane uniaxial stress and in-plane magnetic field that this occurs through a spontaneous lifting of the three-fold rotational symmetry of the nonmagnetic lattice, which relieves the interlayer frustration. We also show through resistivity measurements that uniaxial stress can suppress thermal magnetic disorder within the antiferromagnetic phase.Comment: 9 pages, 9 figure

    Gene structure in the sea urchin Strongylocentrotus purpuratus based on transcriptome analysis

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    A comprehensive transcriptome analysis has been performed on protein-coding RNAs of Strongylocentrotus purpuratus, including 10 different embryonic stages, six feeding larval and metamorphosed juvenile stages, and six adult tissues. In this study, we pooled the transcriptomes from all of these sources and focused on the insights they provide for gene structure in the genome of this recently sequenced model system. The genome had initially been annotated by use of computational gene model prediction algorithms. A large fraction of these predicted genes were recovered in the transcriptome when the reads were mapped to the genome and appropriately filtered and analyzed. However, in a manually curated subset, we discovered that more than half the computational gene model predictions were imperfect, containing errors such as missing exons, prediction of nonexistent exons, erroneous intron/exon boundaries, fusion of adjacent genes, and prediction of multiple genes from single genes. The transcriptome data have been used to provide a systematic upgrade of the gene model predictions throughout the genome, very greatly improving the research usability of the genomic sequence. We have constructed new public databases that incorporate information from the transcriptome analyses. The transcript-based gene model data were used to define average structural parameters for S. purpuratus protein-coding genes. In addition, we constructed a custom sea urchin gene ontology, and assigned about 7000 different annotated transcripts to 24 functional classes. Strong correlations became evident between given functional ontology classes and structural properties, including gene size, exon number, and exon and intron size

    Do echinoderm genomes measure up?

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    Echinoderm genome sequences are a corpus of useful information about a clade of animals that serve as research models in fields ranging from marine ecology to cell and developmental biology. Genomic information from echinoids has contributed to insights into the gene interactions that drive the developmental process at the molecular level. Such insights often rely heavily on genomic information and the kinds of questions that can be asked thus depend on the quality of the sequence information. Here we describe the history of echinoderm genomic sequence assembly and present details about the quality of the data obtained. All of the sequence information discussed here is posted on the echinoderm information web system, Echinobase.org
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