57 research outputs found

    Edna metabarcoding of avocado flowers: ‘Hass’ it got potential to survey arthropods in food production systems?

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    In the face of global biodiversity declines, surveys of beneficial and antagonistic arthropod diversity as well as the ecological services that they provide are increasingly important in both natural and agro-ecosystems. Conventional survey methods used to monitor these communities often require extensive taxonomic expertise and are time-intensive, potentially limiting their application in industries such as agriculture, where arthropods often play a critical role in productivity (e.g. pollinators, pests and predators). Environmental DNA (eDNA) metabarcoding of a novel substrate, crop flowers, may offer an accurate and high throughput alternative to aid in the detection of these managed and unmanaged taxa. Here, we compared the arthropod communities detected with eDNA metabarcoding of flowers, from an agricultural species (Persea americana—‘Hass’ avocado), with two conventional survey techniques: digital video recording (DVR) devices and pan traps. In total, 80 eDNA flower samples, 96 h of DVRs and 48 pan trap samples were collected. Across the three methods, 49 arthropod families were identified, of which 12 were unique to the eDNA dataset. Environmental DNA metabarcoding from flowers revealed potential arthropod pollinators, as well as plant pests and parasites. Alpha diversity levels did not differ across the three survey methods although taxonomic composition varied significantly, with only 12% of arthropod families found to be common across all three methods. eDNA metabarcoding of flowers has the potential to revolutionize the way arthropod communities are monitored in natural and agro-ecosystems, potentially detecting the response of pollinators and pests to climate change, diseases, habitat loss and other disturbances

    Component shape optimisation for enhanced non-destructive testing

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    Determining an optimal component design is fundamental to many applications including many of those in the aerospace, automotive and civil engineering industries. Previously, the compatibility of the component with future non-destructive testing (NDT) requirements has not been considered at the design stage. As a result, NDT operators are often challenged to reliably inspect components with complex geometries. In this paper, a framework is proposed for the optimisation of a component’s shape to maximise the sensitivity and coverage of an interrogating ultrasonic wave, thus enhancing the ability to non-destructively image defects. The design of beam cross-sections are optimised using both a low-dimensional parameterisation with a genetic algorithm, and the level set method which enables more degrees of freedom in the component shape parameterisation. Images of flaws computed using the total focusing method show an 8 dB improvement in the signal to noise ratio for the optimised component as well as a five-fold improvement in the estimate of flaw size. These results show that the NDT-optimised design of components can provide significant improvements in flaw imaging. This in turn assists in extending the lifespan of in-service components and indeed their remanufacturability, which is both environmentally and economically advantageous

    Vouchers for scaling up insecticide-treated nets in Tanzania: Methods for monitoring and evaluation of a national health system intervention

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    BACKGROUND: The Tanzania National Voucher Scheme (TNVS) uses the public health system and the commercial sector to deliver subsidised insecticide-treated nets (ITNs) to pregnant women. The system began operation in October 2004 and by May 2006 was operating in all districts in the country. Evaluating complex public health interventions which operate at national level requires a multidisciplinary approach, novel methods, and collaboration with implementers to support the timely translation of findings into programme changes. This paper describes this novel approach to delivering ITNs and the design of the monitoring and evaluation (M&E). METHODS: A comprehensive and multidisciplinary M&E design was developed collaboratively between researchers and the National Malaria Control Programme. Five main domains of investigation were identified: (1) ITN coverage among target groups, (2) provision and use of reproductive and child health services, (3) "leakage" of vouchers, (4) the commercial ITN market, and (5) cost and cost-effectiveness of the scheme. RESULTS: The evaluation plan combined quantitative (household and facility surveys, voucher tracking, retail census and cost analysis) and qualitative (focus groups and in-depth interviews) methods. This plan was defined in collaboration with implementing partners but undertaken independently. Findings were reported regularly to the national malaria control programme and partners, and used to modify the implementation strategy over time. CONCLUSION: The M&E of the TNVS is a potential model for generating information to guide national and international programmers about options for delivering priority interventions. It is independent, comprehensive, provides timely results, includes information on intermediate processes to allow implementation to be modified, measures leakage as well as coverage, and measures progress over time

    Implementation of an insecticide-treated net subsidy scheme under a public-private partnership for malaria control in Tanzania – challenges in implementation

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    BACKGROUND: In the past decade there has been increasing visibility of malaria control efforts at the national and international levels. The factors that have enhanced this scenario are the availability of proven interventions such as artemisinin-based combination therapy, the wide scale use of insecticide-treated nets (ITNs) and a renewed emphasis in indoor residual house-spraying. Concurrently, there has been a window of opportunity of financial commitments from organizations such as the Global Fund for HIV/AIDS, Tuberculosis and Malaria (GFATM), the President's Malaria Initiative and the World Bank Booster programme. METHODS: The case study uses the health policy analysis framework to analyse the implementation of a public-private partnership approach embarked upon by the government of Tanzania in malaria control - 'The Tanzania National Voucher Scheme'- and in this synthesis, emphasis is on the challenges faced by the scheme during the pre-implementation (2001 - 2004) and implementation phases (2004 - 2005). Qualitative research tools used include: document review, interview with key informants, stakeholder's analysis, force-field analysis, time line of events, policy characteristic analysis and focus group discussions. The study is also complemented by a cross-sectional survey, which was conducted at the Rufiji Health Demographic Surveillance Site, where a cohort of women of child-bearing age were followed up regarding access and use of ITNs. RESULTS: The major challenges observed include: the re-introduction of taxes on mosquito nets and related products, procurement and tendering procedures in the implementation of the GFATM, and organizational arrangements and free delivery of mosquito nets through a Presidential initiative. CONCLUSION: The lessons gleaned from this synthesis include: (a) the consistency of the stakeholders with a common vision, was an important strength in overcoming obstacles, (b) senior politicians often steered the policy agenda when the policy in question was a 'crisis event', the stakes and the visibility were high, (c) national stakeholders in policy making have an advantage in strengthening alliances with international organizations, where the latter can become extremely influential in solving bottlenecks as the need arises, and (d) conflict can be turned into an opportunity, for example the Presidential initiative has inadvertently provided Tanzania with important lessons in the organization of 'catch-up' campaigns

    The Semiotic Fractures of Vulnerable Bodies: Resistance to the Gendering of Legal Subjects

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    While the turn to vulnerability in law responds to a recurrent critique by feminist scholars on the disembodiment of legal personhood, this article suggests that the mobilization of vulnerability in the criminal courts does not necessarily offer female drug mules a direct path to justice. Through an analysis of sentencing appeals of female drug mules in England and Wales, this article presents a feminist critique of the dispositif of the person and its relation to vulnerability. Discourses on drug mules’ vulnerability mobilize the trope of the colonial victim in need of protection, which is often translated into legal mercy. But mercy is rather an expression of biopower which inscribes not only fragility onto the bodies of drug mules by figuring them as exemplar paradigms of colonial subjectivity, but also reinvigorates the dispositif of gender implicit in the legal person. In this set-up, it would appear as if law and politics totalize the registers of life, in this case the contours of vulnerable body. The article suggests we must revisit the image of the wounded body in order to carve out a space for resistance. Drawing on Elaine Scarry and Judith Butler, it suggests vulnerable bodies are marked by a semiotic openness, which renders them subject to appropriation but also able to signify the precarity produced by the law through their resistance to representation

    Growth of tetragonal BaTiO 3

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