31,591 research outputs found

    Transitions to Nematic states in homogeneous suspensions of high aspect ratio magnetic rods

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    Isotropic-Nematic and Nematic-Nematic transitions from a homogeneous base state of a suspension of high aspect ratio, rod-like magnetic particles are studied for both Maier-Saupe and the Onsager excluded volume potentials. A combination of classical linear stability and asymptotic analyses provides insight into possible nematic states emanating from both the isotropic and nematic non-polarized equilibrium states. Local analytical results close to critical points in conjunction with global numerical results (Bhandar, 2002) yields a unified picture of the bifurcation diagram and provides a convenient base state to study effects of external orienting fields.Comment: 3 Figure

    Search for muonic decays of the antiproton at the Fermilab Antiproton Accumulator

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    A search for antiproton decay has been made at the Fermilab Antiproton Accumulator. Limits are placed on six antiproton decay modes which contain a final-state muon. At the 90% C.L. we find that tau/B(mu gamma) > 5.0 x 10^4 yr, tau/B(mu pi0) > 4.8 x 10^4 yr, tau/B(mu eta) > 7.9 x 10^3 yr, tau/B(mu gamma gamma) > 2.3 x 10^4 yr, tau/B(mu K0S > 4.3 x 10^3 yr, and tau/B(mu K0L) > 6.5 x 10^3 yr.Comment: 8 pages + 3 Postscript figure

    Targeted Subsidy for Malaria Control With Treated Nets Using a Discount Voucher System in Tanzania.

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    During the last decade insecticide-treated nets have become a key strategy for malaria control. Social marketing is an appealing tool for getting such nets to poor rural African communities who are most afflicted by malaria. This approach usually involves subsidized prices to make nets and insecticide more affordable and help establish a commercial market. We evaluated a voucher system for targeted subsidy of treated nets in young children and pregnant women in two rural districts of southern Tanzania. Qualitative work involved focus group discussions with community leaders, male and female parents of children under 5 years. In-depth interviews were held with maternal and child health clinic staff and retail agents. Quantitative data were collected through interviewing more than 750 mothers of children under 5 years during a cluster sample survey of child health. The voucher return rate was extremely high at 97% (7720/8000). However, 2 years after the start of the scheme awareness among target groups was only 43% (45/104), and only 12% of women (12/103; 95% CI 4-48%) had used a voucher towards the cost of a net. We found some evidence of increased voucher use among least poor households, compared with the poorest households. On the basis of these results we renewed our information, education and communication (IEC) campaign about vouchers. Discount vouchers are a feasible system for targeted subsidies, although a substantial amount of time and effort may be needed to achieve high awareness and uptake - by which we mean the proportion of eligible women who used the vouchers - among those targeted. Within a poor society, vouchers may not necessarily increase health equity unless they cover a high proportion of the total cost: since some cash is needed when using a voucher as part-payment, poorer women among the target group are likely to have lower uptake than richer women. The vouchers have two important additional functions: strengthening the role of public health services in the context of a social marketing programme and forming an IEC tool to demonstrate the group at most risk of severe malaria

    Elimination of Clock Jitter Noise in Spaceborn Laser Interferometers

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    Space gravitational wave detectors employing laser interferometry between free-flying spacecraft differ in many ways from their laboratory counterparts. Among these differences is the fact that, in space, the end-masses will be moving relative to each other. This creates a problem by inducing a Doppler shift between the incoming and outgoing frequencies. The resulting beat frequency is so high that its phase cannot be read to sufficient accuracy when referenced to state-of-the-art space-qualified clocks. This is the problem that is addressed in this paper. We introduce a set of time-domain algorithms in which the effects of clock jitter are exactly canceled. The method employs the two-color laser approach that has been previously proposed, but avoids the singularities that arise in the previous frequency-domain algorithms. In addition, several practical aspects of the laser and clock noise cancellation schemes are addressed.Comment: 20 pages, 5 figure

    A randomised feasibility study of serial magnetic resonance imaging to reduce treatment times in Charcot neuroarthropathy in people with diabetes (CADOM): A protocol

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    Background Charcot neuroarthropathy is a complication of peripheral neuropathy associated with diabetes which most frequently affects the lower limb. It can cause fractures and dislocations within the foot, which may progress to deformity and ulceration. Recommended treatment is immobilisation and offloading, with a below knee non-removable cast or boot. Duration of treatment varies from six months to more than one year. Small observational studies suggest that repeated assessment with Magnetic Resonance Imaging improves decision making about when to stop treatment, but this has not been tested in clinical trials. This study aims to explore the feasibility of using serial Magnetic Resonance Imaging without contrast in the monitoring of Charcot neuroarthropathy to reduce duration of immobilisation of the foot. A nested qualitative study aims to explore participants’ lived experience of Charcot neuroarthropathy and of taking part in the feasibility study. Methods We will undertake a two arm, open study, and randomise 60 people with a suspected or confirmed diagnosis of Charcot neuroarthropathy from five NHS, secondary care multidisciplinary Diabetic Foot Clinics across England. Participants will be randomised 1:1 to receive Magnetic Resonance Imaging at baseline and remission up to 12 months, with repeated foot temperature measurements and x-rays (standard care plus), or standard care plus with additional three-monthly Magnetic Resonance Imaging until remission up to 12 months (intervention). Time to confirmed remission of Charcot neuroarthropathy with off-loading treatment (days) and its variance will be used to inform sample size in a full-scale trial. We will look for opportunities to improve the protocols for monitoring techniques and the clinical, patient centred, and health economic measures used in a future study. For the nested qualitative study, we will invite a purposive sample of 10-14 people able to offer maximally varying experiences from the feasibility study to take part in semi-structured interviews to be analysed using thematic analysis. Discussion The study will inform the decision whether to proceed to a full-scale trial. It will also allow deeper understanding of the lived experience of Charcot neuroarthropathy, and factors that contribute to engagement in management and contribute to the development of more effective patient centred strategies. Trial registration ISRCTN, ISRCTN, 74101606. Registered on 6 November 2017, http://www.isrctn.com/ISRCTN74101606?q=CADom&filters=&sort=&offset=1&totalResults=1&page=1&pageSize=10&searchType=basic-searc

    Analysis and testing of two-dimensional vented Coanda ejectors with asymmetric variable area mixing sections

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    The analysis of asymmetric, curved (Coanda) ejector flow has been completed using a finite difference technique and a quasi-orthogonal streamline coordinate system. The boundary layer type jet mixing analysis accounts for the effect of streamline curvature in pressure gradients normal to the streamlines and on eddy viscosities. The analysis assured perfect gases, free of pressure discontinuities and flow separation and treated three compound flows of supersonic and subsonic streams. Flow parameters and ejector performance were measured in a vented Coanda flow geometry for the verification of the computer analysis. A primary converging nozzle with a discharge geometry of 0.003175 m x 0.2032 m was supplied with 0.283 cu m/sec of air at about 241.3 KPa absolute stagnation pressure and 82 C stagnation temperature. One mixing section geometry was used with a 0.127 m constant radius Coanda surface. Eight tests were run at spacing between the Coanda surface and primary nozzle 0.01915 m and 0.318 m and at three angles of Coanda turning: 22.5 deg, 45.0 deg, and 75.0 deg. The wall static pressures, the loci of maximum stagnation pressures, and the stagnation pressure profiles agree well between analytical and experimental results

    Development and selection of operational management strategies to achieve policy objectives

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    Since the reform of the EU Common Fisheries Policy in 2002, effort has been devoted to addressing the governance, scientific, social and economic issues required to introduce an ecosystem approach to fisheries management (EAFM) in Europe. Fisheries management needs to support the three pillars of sustainability (ecological, social and economic) and Fisheries Ecosystem Plans (FEPs) have been developed as a tool to assist managers considering the ecological, social and economic implications of their decision. Building upon previous studies (e.g. the FP5-funded European Fisheries Ecosystem Plan project), the core concept of the Making the European Fisheries Ecosystem Plan Operational (MEFEPO) project is to deliver operational frameworks (FEPs) for three regional seas. The project focus is on how best to make current institutional frameworks responsive to an EAFM at regional and pan-European levels in accordance with the principles of good governance. The regional seas selected for the project are the North Sea (NS), North Western Waters (NWW) and South Western Waters (SWW) RAC regions. The aim of this work package (WP5) was to develop operational objectives to achieve the ecological objectives identified for the 3 regional seas in WP2. This report describes the development and implementation of a transparent and formal process that should lead to identification of the “best” operational management strategies for an EAFM, based on sound scientific information and stakeholder involvement (e.g. regional industry groups, citizen groups, managers and other interest groups)
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