6,829 research outputs found

    Truncation of gene F5L partially masks rescue of vaccinia virus strain MVA growth on mammalian cells by restricting plaque size

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    Modified vaccinia virus Ankara (MVA) is a candidate vaccine vector that is severely attenuated due to mutations acquired during several hundred rounds of serial passage in vitro. A previous study used marker rescue to produce a set of MVA recombinants with improved replication on mammalian cells. Here, we extended the characterization of these rescued MVA strains and identified vaccinia virus (VACV) gene F5L as a determinant of plaque morphology but not replication in vitro. F5 joins a growing group of VACV proteins that influence plaque formation more strongly than virus replication and which are disrupted in MVA. These defective genes in MVA confound the interpretation of marker rescue experiments designed to map mutations responsible for the attenuation of this important VACV strain.This work was funded by grants to DCT: NHMRC APP1023141 and ARC FT110100310

    A Numerical Minimization Scheme for the Complex Helmholtz Equation

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    We use the work of Milton, Seppecher, and Bouchitt\'{e} on variational principles for waves in lossy media to formulate a finite element method for solving the complex Helmholtz equation that is based entirely on minimization. In particular, this method results in a finite element matrix that is symmetric positive-definite and therefore simple iterative descent methods and preconditioning can be used to solve the resulting system of equations. We also derive an error bound for the method and illustrate the method with numerical experiments.Comment: 18 pages, 4 figure

    Prospects for Uganda's Dairy Industry

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    The East African country of Uganda might not be thought of as the location of a viable, growing dairy industry. However, Uganda recorded a threefold increase in milk production from 1991 to 2004. While Uganda's dairy industry faces important challenges, the industry possesses advantages that can lead to further increases in milk production if additional, profitable markets can be found for Uganda's milk and dairy products. A major advantage possessed by Uganda's dairy industry is a favorable climate for milk production. Uganda's farmers also have demonstrated a willingness to accept new technologies that can increase milk production. The biggest challenges facing the industry are those associated with poor milk quality and pronounced seasonality of milk production.Uganda Dairy Industry, Uganda's Political and Economic Environment, Pasture-Based Dairy Industry, Poor Milk Quality, Agribusiness, Crop Production/Industries, Farm Management, Food Consumption/Nutrition/Food Safety, Industrial Organization, International Development, International Relations/Trade, Land Economics/Use, Political Economy, Public Economics,

    Real-Time Riverine Particle Image Velocimetry

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    A modular particle image velocimetry program was developed and optimized to read and process video of river surface flows from different sensor types. The program was designed for long-term deployment with the ability to sample data continuously in realtime and save the results in a compact format. The time needed to compute a velocity measurement from video input was reduced by using concurrent processing techniques, multi-threading, and a graphics hardware-based correlation algorithm. When used to process field data on a low power Intel Atom based computer the PIV system was capable of computing up to 64 velocity measurements at a rate of 7.5 frames per second. A more powerful computer equipped with a discrete GPU was capable of computing 4800 velocity measurements at a rate of 7.5 frames per second when using the same PIV data and settings. Processing speed of the GPU correlation module was analyzed using a number of different benchmarks. Results show that the GPU-based correlation algorithm has the potential to improve the PIV processing speed of high-end workstations by as much as 2x and low-end portable computers by 10-20x. Methods were also introduced to improve the quality of PIV measurements on river currents. Processing video of river currents with the standard particle image velocimetry technique produced a large number of inaccurate vectors. Most of these inaccurate vectors were correctly identified and removed by using different confidence scoring and filtering techniques. Results from three different experiments were compared to the velocity measurements of other devices to verify the accuracy of the program. These measurements agree to within 16% difference. These results show that accurate PIV measurements of river surface velocity may be computed in real time even on low end and portable computer hardware

    Pediatric Resuscitation: Evaluation of a Clinical Curriculum

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    Objective: To assess the impact of a 6-hour pediatric resuscitation curriculum on the comfort levels of resident physicians’ evaluation and treatment of critically ill pediatric patients. Methods: An evaluation instrument assessed resident comfort levels, measured on a seven digit Likert scale ranging from significantly uncomfortable to significantly comfortable, in 13 areas of pediatric resuscitation. To complete the curriculum, residents had to demonstrate proficiency in knowledge and procedural skills during mock resuscitation scenarios and on both written and oral examinations. Results: Thirty-one residents participated in the study: 51.6% were pediatric, 12.9% were medicine/pediatric and 35.5% were emergency medicine residents. Participants in the curriculum had little previous experience with pediatric resuscitation (83% had been involved in five or fewer pediatric resuscitations). In all 13 areas of pediatric resuscitation tested, residents reported improvement in comfort levels following the course (p<0.002; Wilcoxon Signed Rank Tests). The most significant changes were observed for the following items: resuscitation of pulseless arrest, performance of cardioversion and defibrillation, performance of intraosseous needle insertion, and drug selection and dosing for rapid sequence intubation. Fewer than 48% of learners rated themselves as comfortable in these areas prior to training, but after completion, more than 80% rated themselves in the comfortable range. All residents but one received passing scores on their written examinations (97%). During the mock resuscitation scenarios and oral examination, 100% of the residents were assessed to have ‘completely’ met the learning objectives and critical actions Conclusion: Implementation of a pediatric resuscitation curriculum improves pediatric and emergency medicine residents’ comfort with the evaluation and treatment of critically ill pediatric patients. This curriculum can be used in residency training to document the acquisition of core competencies, knowledge and procedural skills needed for the evaluation and treatment of the critically ill child. The results reported in this study support using this model of instructional design to implement educational strategies, which will meet the requirements of graduate education

    Cascading blackout overall structure and some implications for sampling and mitigation

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    Cascading blackouts can be thought of as initiating events followed by propagating events that progressively weaken the power system. We briefly discuss the implications for assessing cascading risk by proper sampling from the various sources of uncertainty and for mitigating cascading risk by reducing both the initiating events and their propagation

    The pressure medium as a solid-state oxygen buffer

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    We present a simple method to buffer oxygen fugacity at high pressures and high temperatures where the traditional 'double capsule' method is inappropriate. The pressure medium is doped with a metal which partially reacts with the free oxygen in the pore spaces of the, cell. The resultant finely intergrown metal-metal oxide assemblage buffers the oxygen fugacity in the sample as long as the capsule and furnace materials are oxygen permeable

    Agency and Distributorship Laws in Italy: Guidelines for the Foreign Principal

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    The photoelectric B and V colour observations of the ß Lyrae-type eclipsing binary CN And were made on four nights at the Ege University Observatory. The new light elements, which were calculated by adding new times of minima obtained during the observations to the previous ones, were given. The light curve of the system varies cycle by cycle and the variation is discussed in some extent. © 1989 Kluwer Academic Publishers
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