9,109 research outputs found

    Immunogens and Antigen Processing: Report from a Global HIV Vaccine Enterprise Working Group

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    The Global HIV Vaccine Enterprise convened a meeting of a Working Group in July 2009 to discuss recent progress in rational design of the components of an HIV vaccine, such as inserts, vectors and adjuvants,and in understanding antigen processing and presentation to T and B cells. This Report summarizes the key points of that discussion, and subsequent discussions with the Chairs of the other Enterprise Working Groups, the Enterprise Science Committee, the Enterprise Council and the broader scientific community during open sessions at scientific conferences

    Jacobi-Predictor-Corrector Approach for the Fractional Ordinary Differential Equations

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    We present a novel numerical method, called {\tt Jacobi-predictor-corrector approach}, for the numerical solution of fractional ordinary differential equations based on the polynomial interpolation and the Gauss-Lobatto quadrature w.r.t. the Jacobi-weight function ω(s)=(1s)α1(1+s)0\omega(s)=(1-s)^{\alpha-1}(1+s)^0. This method has the computational cost O(N) and the convergent order ININ, where NN and ININ are, respectively, the total computational steps and the number of used interpolating points. The detailed error analysis is performed, and the extensive numerical experiments confirm the theoretical results and show the robustness of this method.Comment: 24 pages, 5 figure

    Techno-economic evaluation of reducing shielding gas consumption in GMAW whilst maintaining weld quality

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    A new method of supplying shielding gases in an alternating manner has been developed to enhance the efficiency of conventional gas metal arc welding (GMAW). However, the available literature on this advanced joining process is very sparse and no cost evaluation has been reported to date. In simple terms, the new method involves discretely supplying two different shielding gases to the weld pool at predetermined frequencies which creates a dynamic action within the liquid pool. In order to assess the potential benefits of this new method from a technical and cost perspective, a comparison has been drawn between the standard shielding gas composition of Ar/20%CO2, which is commonly used in UK and European shipbuilding industries for carbon steels, and a range of four different frequencies alternating between Ar/20%CO2 and helium. The beneficial effects of supplying the weld shielding gases in an alternating manner were found to provide attractive benefits for the manufacturing community. For example, the present study showed that compared with conventional GMAW, a 17 per cent reduction in total welding cost was achieved in the case of the alternating gas method and savings associated with a reduction in the extent of post-weld straightening following plate distortion were also identified. Also, the mechanical properties of the alternating case highlighted some marginal improvements in strength and Charpy impact toughness which were attributed to a more refined weld microstructure

    The political economy of private firms in China

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    The sweeping change in political economy associated with the spectacular growth of the private sector in China is not much studied in economics literature. This paper fills in this gap. The central subject of this paper is the political economy nature of the Chinese private sector and of the CPC. Empirically, we examine the dynamics of rent creation from the party membership and other political connections when the regime is changed from anti-capitalistic to pro-capitalistic. Endogeneity problems are addressed. We identify the causality of rents and private entrepreneurs’ political connections, and explore the implications of these political elites’ rents for social welfare in terms of productivity.postprin

    Time and Time Functions in Parametrized Non-Relativistic Quantum Mechanics

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    The ``evolving constants'' method of defining the quantum dynamics of time-reparametrization-invariant theories is investigated for a particular implementation of parametrized non-relativistic quantum mechanics (PNRQM). The wide range of time functions that are available to define evolving constants raises issues of interpretation, consistency, and the degree to which the resulting quantum theory coincides with, or generalizes, the usual non-relativistic theory. The allowed time functions must be restricted for the predictions of PNRQM to coincide with those of usual quantum theory. They must be restricted to have a notion of quantum evolution in a time-parameter connected to spacetime geometry. They must be restricted to prevent the theory from making inconsistent predictions for the probabilities of histories. Suitable restrictions can be introduced in PNRQM but these seem unlikely to apply to a reparametrization invariant theory like general relativity.Comment: 18pages, 1postscript figure in separate file, uses REVTEX 3.

    Constraints on Beta Functions from Duality

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    We analyze the way in which duality constrains the exact beta function and correlation length in single-coupling spin systems. A consistency condition we propose shows very concisely the relation between self-dual points and phase transitions, and implies that the correlation length must be duality invariant. These ideas are then tested on the 2-d Ising model, and used towards finding the exact beta function of the qq-state Potts model. Finally, a generic procedure is given for identifying a duality symmetry in other single-coupling models with a continuous phase transition.Comment: LaTeX, 6 page

    The importance of early arthroscopy in athletes with painful cartilage lesions of the ankle: a prospective study of 61 consecutive cases

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    BACKGROUND Ankle sprains are common in sports and can sometimes result in a persistent pain condition. PURPOSE Primarily to evaluate clinical symptoms, signs, diagnostics and outcomes of surgery for symptomatic chondral injuries of the talo crural joint in athletes. Secondly, in applicable cases, to evaluate the accuracy of MRI in detecting these injuries. Type of study: Prospective consecutive series. METHODS Over around 4 years we studied 61 consecutive athletes with symptomatic chondral lesions to the talocrural joint causing persistent exertion ankle pain. RESULTS 43% were professional full time athletes and 67% were semi-professional, elite or amateur athletes, main sports being soccer (49%) and rugby (14%). The main subjective complaint was exertion ankle pain (93%). Effusion (75%) and joint line tenderness on palpation (92%) were the most common clinical findings. The duration from injury to arthroscopy for 58/61 cases was 7 months (5.7–7.9). 3/61 cases were referred within 3 weeks from injury. There were in total 75 cartilage lesions. Of these, 52 were located on the Talus dome, 17 on the medial malleolus and 6 on the Tibia plafond. Of the Talus dome injuries 18 were anteromedial, 14 anterolateral, 9 posteromedial, 3 posterolateral and 8 affecting mid talus. 50% were grade 4 lesions, 13.3% grade 3, 16.7% grade 2 and 20% grade 1. MRI had been performed pre operatively in 26/61 (39%) and 59% of these had been interpreted as normal. Detection rate of cartilage lesions was only 19%, but subchondral oedema was present in 55%. At clinical follow up average 24 months after surgery (10–48 months), 73% were playing at pre-injury level. The average return to that level of sports after surgery was 16 weeks (3–32 weeks). However 43% still suffered minor symptoms. CONCLUSION Arthroscopy should be considered early when an athlete presents with exertion ankle pain, effusion and joint line tenderness on palpation after a previous sprain. Conventional MRI is not reliable for detecting isolated cartilage lesions, but the presence of subchondral oedema should raise such suspicion
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