3,714 research outputs found

    Evaporation of a packet of quantized vorticity

    Full text link
    A recent experiment has confirmed the existence of quantized turbulence in superfluid He3-B and suggested that turbulence is inhomogenous and spreads away from the region around the vibrating wire where it is created. To interpret the experiment we study numerically the diffusion of a packet of quantized vortex lines which is initially confined inside a small region of space. We find that reconnections fragment the packet into a gas of small vortex loops which fly away. We determine the time scale of the process and find that it is in order of magnitude agreement with the experiment.Comment: figure 1a,b,c and d, figure2, figure

    Nutritional Quality of Available Forages for Small Stock during a Drought in an Arid Pastoral Landscape in South Africa

    Get PDF
    This study aimed to assess the nutritional quality of the available forage species during a drought in an arid pastoral system in South Africa. Forage biomass was collected during the wet and dry seasons whilst following livestock herds consisting of boer goats, swakara sheep and mixed breed sheep, in both the summer and winter rainfall regions of the pastoral system. Mineral nutrient content in the plant species revealed that the forages utilized by the livestock generally contained adequate concentrations of Mg, Ca, Na, and K to meet the dietary requirements of the small stock in both the winter and summer rainfall areas. Zinc concentrations in more than half of the forages sampled in the summer rainfall area, during both wet and dry seasons, however, were below the required concentrations for small stock. When considering all plant species utilised, the diets were generally adequate in all mineral nutrients. However, none of the forage species contained sufficiently high concentrations of protein to meet the minimum requirements for small stock. These findings therefore show that pastoralists have to deal with chronic low levels of protein during droughts, and their inability to purchase supplementary feed, or to cultivate fodder crops, or temporary emigrate out of the system puts their livelihoods at high risk to climate change

    Evaluating policy responses to noncommunicable diseases in seven Caribbean countries: challenges to addressing unhealthy diets and physical inactivity

    Get PDF
    This is the final version. Available from the publisher via the DOI in this record.Objective. To identify, assess, and compare existing policies on noncommunicable diseases (NCDs) in the Caribbean, gaps in policy responses, and the factors influencing successful policy development and implementation following the Port of Spain Declaration of 2007. Specifically, to examine policies that target the upstream determinants of two NCD risk factors—unhealthy diets and physical inactivity. Methods. A total of 76 semi-structured interviews with 80 relevant stakeholders in government, the private sector, and civil society were complemented by policy document analysis. Interviews were analyzed pragmatically, framed by the CARICOM government commitments, the WHO NCD Action Plan, a Multiple Streams framework approach, and realist evaluation ideas. Results. The most widely-reported policy successes involved health promotion activities (e.g., school meal programs) that leveraged multisectoral collaboration among government ministries, such as Health, Education, and Agriculture. Large policy gaps still exist around creating legislative, physical, and social environments to support healthy eating and physical activity at the population level. Multisectoral NCD commissions successfully reached across sectors, but had limited influence on policy development. Different policy levels emerged with national-level policies considered a lengthy process, while “On-the-ground” programming was considered faster to implement than national policies. External barriers included a reliance on food imports enabled by international trade agreements limited availability, quality, and affordability of healthy foods. International pushback limited legislation to reduce food imports and the absence of an international/regional framework, similar to the Framework Convention on Tobacco Control, further impedes efforts. Conclusions. Regional collaboration and political support across sectors are essential to accelerating the pace of action to support healthy eating and active living environments. Policy “blueprints” could accelerate the process of development. Regional “NCD champions” could spearhead such responses and approaches.International Development Research Centr

    Health research systems in change: the case of ‘Push the Pace’ in the National Institute for Health Research

    Get PDF
    Background Those running well-organised health research systems are likely to be alert for ways in which they might increase the quality of the services they provide and address any problems identified. This is important because the efficiency of the research system can have a major impact on how long it takes for new treatments to be developed and reach patients. This opinion piece reflects on the experience and learning of the United Kingdom-based National Institute for Health Research (NIHR) when it implemented continuous improvement activity to improve its processes. Discussion This paper describes the structure and work of the NIHR and why, despite is successes as a health research system and ongoing local continuous improvement, it believed in the value of an organisation-wide continuous improvement activity. It did this by implementing an approach called ‘Push the Pace’. Initially, the organisation focused on reducing the amount of time it took for research to transition from an early concept to evidence that changes lives. This scrutiny enabled the NIHR to realise further areas of improvement it could make – additional goals were increased transparency, process simplification, and improved customer and stakeholder experience. We discuss our experience of Push the Pace with reference to literature on continuous improvement. Conclusion Continuous improvement is a cycle, an activity that is done constantly and over time, rather than an act or linear activity (such as Push the Pace). We believe that the work of Push the Pace has initiated a strong commitment to a culture of continuous improvement in the NIHR. This is significant because culture change is widely recognised as immensely challenging, particularly in such a large and distributed organisation. However, our biggest challenge will be to enable all staff and stakeholders of the NIHR to participate in the continuous improvement cycle

    Hypocrea rufa/Trichoderma viride: a reassessment, and description of five closely related species with and without warted conidia

    Get PDF
    The type species of the genus Hypocrea (Hypocreaceae, Hypocreales, Ascomycota, Fungi), H. rufa, is re-defined and epitypified using a combination of phenotype (morphology of teleomorphs and anamorphs, and characteristics in culture) and phylogenetic analyses of the translation-elongation factor 1α gene. Its anamorph, T. viride, the type species of Trichoderma, is re-described and epitypified. Eidamia viridescens is combined as Trichoderma viridescens and is recognised as one of the most morphologically and phylogenetically similar relatives of T. viride. Its teleomorph is newly described as Hypocrea viridescens. Contrary to frequent citations of H. rufa and T. viride in the literature, this species is relatively rare. Although both T. viride and T. viridescens have a wide geographic distribution, their greatest genetic diversity appears to be in Europe and North America. Hypocrea vinosa is characterised and its anamorph, T. vinosum sp. nov., is described. Conidia of T. vinosum are subglobose and warted. The new species T. gamsii is proposed. It shares eidamia-like morphology of conidiophores with T. viridescens, but it has smooth, ellipsoidal conidia that have the longest L/W ratio that we have seen in Trichoderma. Trichoderma scalesiae, an endophyte of trunks of Scalesia pedunculata in the Galapagos Islands, is described as new. It only produces conidia on a low-nutrient agar to which filter paper has been added. Additional phylogenetically distinct clades are recognised and provisionally delimited from the species here described. Trichoderma neokoningii, a T. koningii-like species, is described from a collection made in Peru on a fruit of Theobroma cacao infected with Moniliophthora roreri

    The Diversity of Poisonous Plant Patches in the Arid Rangelands of Namaqualand, South Africa

    Get PDF
    The Namaqualand region in South Africa is part of the richest arid biodiversity hotspot in the world. Plant distribution and diversity here are impacted by various biophysical and anthropogenic factors. In these landscapes, poisonous plant patches, which pose serious threats to livestock, are widespread but their contribution to the regions biodiversity are not fully understood. This study assessed their plant diversity and compared its matrix. This study was conducted in the semi-arid to arid Steinkopf pastoral area located in Namaqualand where livestock is still herded daily. Twenty-five paired sites were selected based on the dominance of poisonous plants within the genera Tylecodon, Euphorbia and Adromischus. Within these sites, the number and abundance of different plant species were recorded and categorised into different plant functional types. Results showed a significant difference in Shannon Wiener plant diversity where poisonous plant patches displayed a greater diversity compared to sites sampled in the matrix. We interpret these findings as a consequence of herding in the region, where herders do not allow their animals to graze on or near poisonous plant patches. As such, palatable plants, which are absent or low in abundance in the surrounding landscape have a refuge where they can survive and set seed. This study provides evidence that the ethnobotanical knowledge of herders and palette of livestock are also major contributors to the spatial distribution and diversity of plant species in the arid biodiversity hotspot

    Decay of quantised vorticity by sound emission

    Full text link
    It is thought that in a quantum fluid sound generation is the ultimate sink of turbulent kinetic energy in the absence of any other dissipation mechanism near absolute zero. We show that a suitably trapped Bose-Einstein condensate provides a model system to study the sound emitted by accelerating vortices in a controlled way.Comment: 6 pages, 3 figure

    Human Galectin-9 Is a Potent Mediator of HIV Transcription and Reactivation.

    Get PDF
    Identifying host immune determinants governing HIV transcription, latency and infectivity in vivo is critical to developing an HIV cure. Based on our recent finding that the host factor p21 regulates HIV transcription during antiretroviral therapy (ART), and published data demonstrating that the human carbohydrate-binding immunomodulatory protein galectin-9 regulates p21, we hypothesized that galectin-9 modulates HIV transcription. We report that the administration of a recombinant, stable form of galectin-9 (rGal-9) potently reverses HIV latency in vitro in the J-Lat HIV latency model. Furthermore, rGal-9 reverses HIV latency ex vivo in primary CD4+ T cells from HIV-infected, ART-suppressed individuals (p = 0.002), more potently than vorinostat (p = 0.02). rGal-9 co-administration with the latency reversal agent "JQ1", a bromodomain inhibitor, exhibits synergistic activity (p<0.05). rGal-9 signals through N-linked oligosaccharides and O-linked hexasaccharides on the T cell surface, modulating the gene expression levels of key transcription initiation, promoter proximal-pausing, and chromatin remodeling factors that regulate HIV latency. Beyond latent viral reactivation, rGal-9 induces robust expression of the host antiviral deaminase APOBEC3G in vitro and ex vivo (FDR<0.006) and significantly reduces infectivity of progeny virus, decreasing the probability that the HIV reservoir will be replenished when latency is reversed therapeutically. Lastly, endogenous levels of soluble galectin-9 in the plasma of 72 HIV-infected ART-suppressed individuals were associated with levels of HIV RNA in CD4+ T cells (p<0.02) and with the quantity and binding avidity of circulating anti-HIV antibodies (p<0.009), suggesting a role of galectin-9 in regulating HIV transcription and viral production in vivo during therapy. Our data suggest that galectin-9 and the host glycosylation machinery should be explored as foundations for novel HIV cure strategies

    Avaliação do desempenho de fungos entomopatogênicos sobre fêmeas de Dactylopius opuntiae (Hemiptera: dactylopiidae) em condições de laboratório.

    Get PDF
    O OBJETIVO DESTE TRABALHO FOI INVESTIGAR O POTENCIAL DOS FUNGOS ENTOMOPATOGÊNICOS NO CONTROLE DE D. OPUNTIAE.Resumo 1669-1

    Nutritional quality of Calobota sericea fodders. A preliminary assessment

    Get PDF
    This study aimed to provide preliminary information regarding the nutritional quality of Calobota sericea, a preferred perennial legume forage species from the water-limited rangelands of South Africa. Calobota sericea plant samples were collected from the Namaqualand rangelands in the wet and dry season and analysed for secondary compounds, fibre, protein and mineral nutrient content. The results from the fibre analyses were used to determine the digestibility and energy content of fodders. Preliminary results indicate that C. sericea fodders are of better nutritional quality in the wet season and that protein content, digestibility and energy content is sufficient for maintenance of lambs and dry ewes. The energy content, however, was not sufficient for maintenance of pregnant and lactating ewes. Furthermore, certain mineral nutrients (Na, P and K) were not found in sufficient concentrations in this species, and it was thus suggested that further investigation is needed into whether fertilisation could potentially improve the protein, digestibility and mineral nutrient content of C. sericea fodders
    corecore