2,354 research outputs found

    An implementation of synthetic generation of wind data series

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    Wind power fluctuation is a major concern of large scale wind power grid integration. To test methods proposed for wind power grid integration, a large amount of wind data with time series are necessary and will be helpful to improve the methods. Meanwhile, due to the short operation history of most wind farms as well as limitations of data collections, the data obtained from wind farms could not satisfy the needs of data analysis. Consequently, synthetic generation of wind data series could be one of the effective solutions for this issue. In this paper, a method is presented for generating wind data series using Markov chain. Due to the high order Markov chain, the possibility matrix designed for a wind farm could cost a lot of memory, which is a problem with current computer technologies. Dynamic list will be introduced in this paper to reduce the memory required. Communication errors are un-avoidable on long way signal transmission between the control centre and wind farms. Missing of data always happens in the historical wind data series. Using these data to generate wind data series may result in some mistakes when searching related elements in the probability matrix. An adaptive method will be applied in this paper to solve the problem. The proposed method will be verified using a set of one-year historical data. The results show that the method could generate wind data series in an effective way. © 2013 IEEE.published_or_final_versio

    Determination and Distribution Study of Pogostone in Rat Tissues by Ultra-Fast Liquid Chromatography

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    Purpose: To develop and validate a rapid, sensitive and reliable ultra-fast liquid chromatography (UFLC) method with photodiode array (PDA) detection for the determination of pogostone (PO) in rat tissues using honokiol as internal standard (IS).Methods: Rats were randomly divided into two groups (intravenous administration group and oral administration group) and given of a single dose of 10 mg/kg PO by intravenous administration and oral administration, respectively. After intravenous injection, the rats were sacrificed at 15, 60 and 360 min, while rats, after oral administration, were euthanasized at 30, 90 and 360 min, respectively. For the analysis of the preparation, optimal chromatographic conditions were determined using Acquity UPLC BEH C18 column with acetonitrile-water containing 0.1 % formic acid (55:45, v/v) as the mobile phase, at a flow rate of 400 μL/min. UV detection wavelength was set at 310 nm with temperature maintained at 30 °C.Results: Good linear relationship of calibration curve (r > 0.9984) was achieved over the range of 0.1 - 40 μg/mL for all the tissue samples. The limit of quantification (LOQ) and limit of detection (LOD) were 0.1 and 0.05 μg/mL, respectively. This method proved to have good precision, accuracy, stability, extraction recovery and matrix effect for tissue distribution studies of PO in rats.Conclusion: The developed method is suitable for tissue distribution studies in rats following intravenous and oral administration of PO at a dose of 10 mg/kg.Keywords: Ultra-fast liquid chromatography, Tissue distribution, Pogostone, Honokiol, Rat

    Mutational Analyses of the Influenza A Virus Polymerase Subunit PA Reveal Distinct Functions Related and Unrelated to RNA Polymerase Activity

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    Influenza A viral polymerase is a heterotrimeric complex that consists of PA, PB1, and PB2 subunits. We previously reported that a di-codon substitution mutation (G507A-R508A), denoted J10, in the C-terminal half of PA had no apparent effect on viral RNA synthesis but prevented infectious virus production, indicating that PA may have a novel role independent of its polymerase activity. To further examine the roles of PA in the viral life cycle, we have now generated and characterized additional mutations in regions flanking the J10 site from residues 497 to 518. All tested di-codon mutations completely abolished or significantly reduced viral infectivity, but they did so through disparate mechanisms. Several showed effects resembling those of J10, in that the mutant polymerase supported normal levels of viral RNA synthesis but nonetheless failed to generate infectious viral particles. Others eliminated polymerase activity, in most cases by perturbing the normal nuclear localization of PA protein in cells. We also engineered single-codon mutations that were predicted to pack near the J10 site in the crystal structure of PA, and found that altering residues K378 or D478 each produced a J10-like phenotype. In further studies of J10 itself, we found that this mutation does not affect the formation and release of virion-like particles per se, but instead impairs the ability of those particles to incorporate each of the eight essential RNA segments (vRNAs) that make up the viral genome. Taken together, our analysis identifies mutations in the C-terminal region of PA that differentially affect at least three distinct activities: protein nuclear localization, viral RNA synthesis, and a trans-acting function that is required for efficient packaging of all eight vRNAs

    Local steroid injection for moderately severe idiopathic carpal tunnel syndrome: Protocol of a randomized double-blind placebo-controlled trial (NCT 00806871)

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    <p>Abstract</p> <p>Background</p> <p>Patients with idiopathic carpal tunnel syndrome (CTS) are commonly treated with steroid injection into or proximal to the carpal tunnel. However, evidence for its efficacy beyond one month has not been established in randomized placebo-controlled trials. The primary aim of this randomized trial is to assess the efficacy of steroid injection into the carpal tunnel in relieving symptoms of CTS in patients with symptoms of such severity to warrant surgical treatment but have not been treated with steroid injection.</p> <p>Methods/Design</p> <p>The study is a randomized double-blind placebo-controlled trial. Patients referred to one orthopedic department because of CTS are screened. Eligibility criteria are age 18 to 70 years, clinical diagnosis of primary idiopathic CTS and abnormal nerve conduction tests or clinical diagnosis made independently by two orthopedic surgeons, failed treatment with wrist splinting, symptom severity of such magnitude that the patient is willing to undergo surgery, no severe sensory loss or thenar muscle atrophy, and no previous steroid injection for CTS. A total of 120 patients will be randomized to injection of 80 mg Methylprednisolone, 40 mg Methylprednisolone, or normal saline, each also containing 10 mg Lidocaine. Evaluation at baseline and at 5, 10, 24 and 52 weeks after injection includes validated questionnaires (CTS symptom severity scale, <it>Quick</it>DASH and SF-6D), adverse events, physical examination by a blinded assessor, and nerve conduction tests. The primary outcome measures are change in the CTS symptom severity score at 10 weeks and the rate of surgery at 52 weeks. The secondary outcome measures are the score change in the CTS symptom severity scale at 52 weeks, time to surgery, and change in <it>Quick</it>DASH and SF-6D scores and patient satisfaction at 10 and 52 weeks. The primary analysis will be carried out using mixed model analysis of repeated measures.</p> <p>Discussion</p> <p>This paper describes the rationale and design of a double-blind, randomized placebo-controlled trial that aims to determine the efficacy of two different doses of steroid injected into the carpal tunnel in patients with moderately severe idiopathic CTS.</p> <p>Trial registration</p> <p>Clinicaltrials.gov identifier NCT00806871</p

    Crystallisation route map

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    A route map for the assessment of crystallisation processes is presented. A theoretical background on solubility, meta-stable zone width, nucleation and crystal growth kinetics is presented with practical examples. The concepts of crystallisation hydrodynamics and the application of population balances and computational fluid dynamics for modelling crystallisation processes and their scaling up are also covered

    A branch and efficiency algorithm for the optimal design of supply chain networks

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    Supply chain operations directly affect service levels. Decision on amendment of facilities is generally decided based on overall cost, leaving out the efficiency of each unit. Decomposing the supply chain superstructure, efficiency analysis of the facilities (warehouses or distribution centers) that serve customers can be easily implemented. With the proposed algorithm, the selection of a facility is based on service level maximization and not just cost minimization as this analysis filters all the feasible solutions utilizing Data Envelopment Analysis (DEA) technique. Through multiple iterations, solutions are filtered via DEA and only the efficient ones are selected leading to cost minimization. In this work, the problem of optimal supply chain networks design is addressed based on a DEA based algorithm. A Branch and Efficiency (B&E) algorithm is deployed for the solution of this problem. Based on this DEA approach, each solution (potentially installed warehouse, plant etc) is treated as a Decision Making Unit, thus is characterized by inputs and outputs. The algorithm through additional constraints named “efficiency cuts”, selects only efficient solutions providing better objective function values. The applicability of the proposed algorithm is demonstrated through illustrative examples

    A Prompt to the Web: The Media and Health Information Seeking Behaviour

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    UNLABELLED: OBJECTIVE, DESIGN, SETTING AND PARTICIPANTS: The objective was to investigate media influence on consumers' health related behaviours. A cross-sectional survey of randomly selected adults (18+ years) residing in the Hunter Region of New South Wales Australia was conducted. The sample was selected using a combination of the white pages and random digit dialling. MAIN OUTCOME MEASURES: The proportions of respondents who recalled seeing or hearing about conditions or treatments in the media over the 12 months prior to interview (August 2009-August 2010) and their subsequent health related behaviour. RESULTS: Although most survey participants reported seeking health information from their doctors, around two-thirds of survey participants (551, 68.8%) recalled hearing, seeing or reading about one or more medical conditions (total = 1097 instances) in the mainstream media over the past 12 months. Almost 40% of respondents (307, 38.4%) stated that they had looked for more information about a condition as a result of hearing about it in the media, and most used the internet (269, 87.4%). More than a quarter of respondents (215, 26.9%) indicated that they had asked their doctor about a condition they had heard about in the media. Around half of those who asked their doctor (109, 50.6%) reported that their inquiry resulted in them receiving treatment, of whom almost half (53, 48.3%) reported being prescribed a medicine. CONCLUSION: The survey results show that consumers become aware of medicines through traditional media and then to learn more often turn to the internet where quality of information may be poor

    A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

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    We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package
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