7,018 research outputs found

    Lax pair and Darboux transformation of noncommutative U(N) principal chiral model

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    We present a noncommutative generalization of Lax formalism of U(N) principal chiral model in terms of a one-parameter family of flat connections. The Lax formalism is further used to derive a set of parametric noncommutative B\"{a}cklund transformation and an infinite set of conserved quantities. From the Lax pair, we derive a noncommutative version of the Darboux transformation of the model.Comment: 1+20 page

    On non commutative sinh-Gordon Equation

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    We give a noncommutative extension of sinh-Gordon equation. We generalize a linear system and Lax representation of the sinh-Gordon equation in noncommutative space. This generalization gives a noncommutative version of the sinh-Gordon equation with extra constraints, which can be expressed as global conserved currents.Comment: 7 Page

    The Odyssey Approach for Optimizing Federated SPARQL Queries

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    Answering queries over a federation of SPARQL endpoints requires combining data from more than one data source. Optimizing queries in such scenarios is particularly challenging not only because of (i) the large variety of possible query execution plans that correctly answer the query but also because (ii) there is only limited access to statistics about schema and instance data of remote sources. To overcome these challenges, most federated query engines rely on heuristics to reduce the space of possible query execution plans or on dynamic programming strategies to produce optimal plans. Nevertheless, these plans may still exhibit a high number of intermediate results or high execution times because of heuristics and inaccurate cost estimations. In this paper, we present Odyssey, an approach that uses statistics that allow for a more accurate cost estimation for federated queries and therefore enables Odyssey to produce better query execution plans. Our experimental results show that Odyssey produces query execution plans that are better in terms of data transfer and execution time than state-of-the-art optimizers. Our experiments using the FedBench benchmark show execution time gains of at least 25 times on average.Comment: 16 pages, 10 figure

    Facilitating inter-spousal communication for birth spacing--a feasibility study of Pakistani couples for policy implications

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    Objective: To test three practices introduced to couples for adaptation of a non-permanent modern method of family planning and the role that each partner played during the process.SETTING: Urban and sub-urban areas of Karachi, Lahore, and Quetta.Methods: \u27Behavioral trials\u27 was conducted which is a formative research method in which researcher and participants negotiate behavior(s) that the participant agrees to try for a specific amount of time. Interviews were conducted on 72 married couples (144 men and women) living in urban and sub-urban areas of Karachi, Lahore and Quetta. Study participants were either non-users of modern methods of family panning, or using traditional methods. The three behaviors negotiated were: a) Discuss benefits of birth spacing with spouse; b) discuss specific methods of family planning and decide on the most appropriate one and c) initiate use of a modern temporary method of family planning.Results: After the introduction of first practice, of 72 couples 38 reported failure to initiate the discussion with their spouse. Where women initiated the discussion the response from spouse was not as favorable as where men initiated the discussion. After introduction of second practice 28 couples were successful in discussing about selection of a family planning method. Twenty-four couples finally selected and used a method. Traditional users were more likely to adopt a modern method than non-users, especially those with 3-5 children.CONCLUSION: Strategies to cultivate a culture of inter-spousal communication on use of family planning methods should be developed as a component of family planning programs

    A dual-mass resonant mems gyroscope design with electrostatic tuning for frequency mismatch compensation

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    The micro-electro-mechanical systems (MEMS)-based sensor technologies are considered to be the enabling factor for the future development of smart sensing applications, mainly due to their small size, low power consumption and relatively low cost. This paper presents a new structurally and thermally stable design of a resonant mode-matched electrostatic z-axis MEMS gyroscope considering the foundry constraints of relatively low cost and commercially available silicon-on-insulator multi-user MEMS processes (SOIMUMPs) microfabrication process. The novelty of the proposed MEMS gyroscope design lies in the implementation of two separate masses for the drive and sense axis using a unique mechanical spring configuration that allows minimizing the cross-axis coupling between the drive and sense modes. For frequency mismatch compensation between the drive and sense modes due to foundry process uncertainties and gyroscope operating temperature variations, a comb-drive-based electrostatic tuning is implemented in the proposed design. The performance of the MEMS gyroscope design is verified through a detailed coupled-field electric-structural-thermal finite element method (FEM)-based analysis

    Risk Factors of Diarrhoea in Malnourished Children Under Age of 5 Years

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    Background: Acute infectious enteritis remains one of the commonest causes of death among infants and children in developing countries. Acute enteritis is defined as a loss of stool consistency with pasty or liquid stools, and/or an increase in stool frequency to more than three stools in 24 hours with or without fever or vomiting. Human survival depends on the secretion and reabsorption of fluid and electrolytes in the intestinal tract. The objective of the study is to evaluate the risk factors of diarrhoea in children under age of 5 years. Methodology: It was an observational study. Study was completed in about six months. Non-probability purposive sampling technique was used. In this study, 270 samples were taken from Diarrheal ward of The Children Hospital Lahore, Pakistan. Results: In this study, out of 270 patients, 58.52% were males and 41.48% were females. 90.37% patients were vaccinated. 54.81% had weaning history. 91.85% patients had feeding history. 29.26% had blood in stool. 96.67% patients were dehydrated. 95.56% patients had loose watery diarrhoea. 62.96% patients used boiled water. 58.52% patients consumed less than half litre of water, 30.00% patients consumed 1 litre of water and 11.48% patients consumed > 1 litre of water. 49.18% patients had proper hygiene. 38.15% mothers of patients were well educated. 40.37% patients had model household condition. 57.41% patients lived in rural area and 42.59% patients lived in urban area. Conclusion: The variation in the level of diarrheal morbidity was well explained by maternal education, income, personal hygiene, refuse disposal system and the effect of health extension programme

    Germination of Themeda triandra (Kangaroo grass) as affected by different environmental conditions and storage periods

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    Low rainfall in range areas restricts germination, growth and development of majority of range grasses. However, germination and establishment potential of forage grasses vary and depends on environmental conditions. Themeda triandra is an excellent known grass to grow under different environmental conditions. T. triandra naturally grows over an extensive geographical range on many soil types. Germination of T. triandra is the key factor in its establishment or re-establishment because its germination varies widely which is also affected by storage periods of seed. Germination response of Themeda to storage period was conducted in the laboratory. Four storage periods (Fresh seed, 6, 12 and 18 months old) seeds were sown in laboratory in germination trays placed in growth chamber in completely randomized design. Germination was counted till 40 days after sowing and percentage calculated thereafter. The 12 month old seeds gave the maximum 84% germination. On the basis of laboratory experiment, 12 months seeds were sown at 3 diverse locations (Rawalpindi, Jhelum and Talagang) with 4 spacing treatments (20, 30, 40 and Broadcast) in completely randomized block design. Germination was recorded for 40 days after sowing (DAS) and the maximum germination was observed in 25 - 30 DAS depending on the environmental conditions of experimental sites. Closer plant spacing (20 cm) gave the maximum (79%) germination at high rainfall area (Rawalpindi) while the least (52%) was recorded for the wider plant spacing at low rain fall area (Talagang)

    How Diverse Are Federated Query Execution Plans Really?

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