239 research outputs found

    The pathophysiology of diastolic heart failure

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    Whilst resting disturbances of both diastolic and long-axis systolic function are observed in patients with heart failure who have normal left ventricular ejection fraction, recent evidence suggests that dynamic disturbances in cardiac function occur during exercise. A paradoxical slowing of left ventricular active relaxation during exercise limits cardiac filling and therefore stroke volume and appears to be due to the combination of cardiac energetic impairment and disturbed ventricular-vascular coupling

    Balloon Venoplasty of Subclavian Vein and Brachiocephalic Junction to Enable Left Ventricular Lead Placement for Cardiac Resynchronisation Therapy

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    AbstractThis report describes the successful implantation of a LV lead using balloon venoplasty to overcome a very tight stenosis of the right subclavian vein / brachiocephalic junction for cardiac resynchronisation therapy (CRT-P) in a patient with a right sided CRT-P system and a failed epicardial LV lead. It is important for device implanters to be familiar with interventional equipments and techniques such as balloon venoplasty to overcome difficult venous access

    Determine the source term of a two-dimensional heat equation

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    Let Ω\Omega be a two-dimensional heat conduction body. We consider the problem of determining the heat source F(x,t)=φ(t)f(x,y)F(x,t)=\varphi(t)f(x,y) with φ\varphi be given inexactly and ff be unknown. The problem is nonlinear and ill-posed. By a specific form of Fourier transforms, we shall show that the heat source is determined uniquely by the minimum boundary condition and the temperature distribution in Ω\Omega at the initial time t=0t=0 and at the final time t=1t=1. Using the methods of Tikhonov's regularization and truncated integration, we construct the regularized solutions. Numerical part is given.Comment: 18 page

    Performance of export-oriented small and medium-sized manufacturing enterprises in Viet Nam

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    The study recommends the formulation of policies that support the development of business linkages and networking, and which promote subcontracting arrangements between small and large enterprises or between domestic firms and foreign investment enterprises. It is also necessary to support and facilitate the direct involvement of SMMEs in exporting or indirectly through large manufacturing enterprises.Export-oriented, SME,SMME, Viet Nam

    Determination of the body force of a two-dimensional isotropic elastic body

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    Let Ω\Omega represent a two−-dimensional isotropic elastic body. We consider the problem of determining the body force FF whose form ϕ(t)(f1(x),f2(x))\phi(t)(f_1(x),f_2(x)) with ϕ\phi be given inexactly. The problem is nonlinear and ill-posed. Using the Fourier transform, the methods of Tikhonov's regularization and truncated integration, we construct a regularized solution from the data given inexactly and derive the explicitly error estimate. Numerical part is givenComment: 23 page

    Optimal solutions for fixed head short-term hydrothermal system scheduling problem

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    In this paper, optimal short-term hydrothermal operation (STHTO) problem is determined by a proposed high-performance particle swarm optimization (HPPSO). Control variables of the problem are regarded as an optimal solution including reservoir volumes of hydropower plants (HdPs) and power generation of thermal power plants (ThPs) with respect to scheduled time periods. This problem focuses on reduction of electric power generation cost (EPGC) of ThPs and exact satisfactory of all constraints of HdPs, ThPs and power system. The proposed method is compared to earlier methods and other implemented methods such as particle swarm optimization (PSO), constriction factor (CF) and inertia weight factor (IWF)-based PSO (FCIW-PSO), two time-varying acceleration coefficient (TTVACs)-based PSO (TVAC-PSO), salp swarm algorithm (SSA), and Harris hawk algorithm (HHA). By comparing EPGC from 100 trial runs, speed of search and simulation time, the suggested HPPSO method sees it is more robust than other ones. Thus, HPPSO is recommended for applying to the considered and other problems in power systems

    Determining optimal location and size of capacitors in radial distribution networks using moth swarm algorithm

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    In this study, the problem of optimal capacitor location and size determination (OCLSD) in radial distribution networks for reducing losses is unraveled by moth swarm algorithm (MSA). MSA is one of the most powerful meta-heuristic algorithm that is taken from the inspiration of the food source finding behavior of moths. Four study cases of installing different numbers of capacitors in the 15-bus radial distribution test system including two, three, four and five capacitors areemployed to run the applied MSA for an investigation of behavior and assessment of performances. Power loss and the improvement of voltage profile obtained by MSA are compared with those fromother methods. As a result, it can be concluded that MSA can give a good truthful and effective solution method for OCLSD problem

    ICT Integration in Developing Competence for Pre- Service Mathematics Teachers A Case Study from Six Universities in Vietnam

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    Competence structure that pre-service teachers need to develop to become a future teacher has been defined since the 1930s. For pre-service mathematics teachers, their competence has its own characteristics. ICT integration in developing competence for pre-service mathematics teachers has been been proved to be effective in many previous studies. In Vietnam, the Ministry of Education and Training (MOET) has recommended the use of ICT to enhance teaching-learning activities in schools and universities, therefore, there have been many studies on ICT intergration at different educational levels. However, there are only a few studies on the use ICT integration in developing competence for pre-service mathematics teachers. This paper presents results from a research on the feasibility of ICT integration in developing competence of Vietnamese pre-service mathematics teachers. The research was conducted by surveying on a randomly selected of 297 pre-service mathematics teachers and 40 mathematics lecturers in six universities which provide mathematics training programs. Results show that despite of the availability of technologies, ICT integration in training pre-service teachers is still limited. In addition, ICT integration in teaching activities of mathematics teachers is not really effective because the levels of their ICT skills are very different. Pre-service mathematics teachers have the ability to use ICT equipment, and good accessibility to learning systems, but their use of the learning management systems (LMS) is limited. This study can be a reference for future studies to test the effective of ICT integration in training pre-service teachers when designing activities to develop feasibly and effectively their competence

    A SURVEY ON THE DIFFICULTIES IN WRITING ESSAYS OF ENGLISH MAJORED SOPHOMORES AT TAY DO UNIVERSITY, VIETNAM

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    This thesis “A study on the difficulties in writing essays of English-majored sophomores at Tay Do University” was conducted to examine the difficulties that second-year students majoring in English often met in writing essays. For this purpose, the participants in this study were 100 English majored sophomores in classes 14A, 14B and 14C at Tay Do University. The interview with 3 extended statements for English majored teachers and a questionnaire with 25 closed statements for students is used as instruments to collect the data. The data from the interview and questionnaire were collected to make clear and prove the problems that the students have had in writing essays. The study figured out some difficulties about background knowledge, vocabulary, grammar structure, idea arrangement and orthography in writing essays faced by English majors sophomores at Tay Do University. Besides, this study also helps students realize their challenges and improve their writing essays.  Article visualizations
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