479 research outputs found

    Parameter estimation of electric power transformers using Coyote Optimization Algorithm with experimental verification

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    In this work, the Coyote Optimization Algorithm (COA) is implemented for estimating the parameters of single and three-phase power transformers. The estimation process is employed on the basis of the manufacturer's operation reports. The COA is assessed with the aid of the deviation between the actual and the estimated parameters as the main objective function. Further, the COA is compared with well-known optimization algorithms i.e. particle swarm and Jaya optimization algorithms. Moreover, experimental verifications are carried out on 4 kVA, 380/380 V, three-phase transformer and 1 kVA, 230/230 V, single-phase transformer. The obtained results prove the effectiveness and capability of the proposed COA. According to the obtained results, COA has the ability and stability to identify the accurate optimal parameters in case of both single phase and three phase transformers; thus accurate performance of the transformers is achieved. The estimated parameters using COA lead to the highest closeness to the experimental measured parameters that realizes the best agreements between the estimated parameters and the actual parameters compared with other optimization algorithms

    A randomized comparative study between selective walking spinal anesthesia and general anesthesia for anorectal surgeries in outpatient settings

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    AbstractBackgroundSpinal anesthesia is gradually increasing in ambulatory setting. The limiting factor to the more widespread use of spinal anesthesia in the outpatient setting refers to the effect of residual block. Selective spinal anesthesia (SSA) with low dose lidocaine was compared with modern general anesthesia (GA) technique in day care anorectal surgeries.ObjectiveOur objectives in this study was to compare SSA with propofol and fentanyl based modern GA as regard to 1 – operating conditions 2 – patients’ and surgeon’s satisfaction, 3 – intraoperative, postoperative adverse events and 4 – recovery profiles in ambulatory anorectal surgeries.MethodsProspective randomized clinical study was conducted on 60 patients undergoing elective day case anorectal surgery. The patients were randomly allocated into one of two groups (GA and SSA groups) of 30 patients each. In GA group anesthesia was induced with intravenous fentanyl (2μg/kg) and propofol (2–3mg/kg). Airway was secured with I-gel supraglottic airway. Anesthesia was maintained by sevoflurane 1.5–2%, nitrous oxide 60% in oxygen mixture. SSA group patients received spinal anesthesia with lidocaine 20mg and fentanyl 25μg to a total volume of 3ml with sterile water for injection. Intraoperative, postoperative and home adverse events, time to ambulate, time to home discharge, patients’ and surgeon’s satisfactions were statistically compared between both groups.ResultsBoth anesthetic techniques showed acceptable operating conditions and high rate of patients’ satisfaction. Low pain intensity, shorter time to ambulate and home discharge in SSA compared to GA with a p value<0.001. Intraoperative hemodynamic stability was reported in both groups. No major postoperative or home adverse events in both groups.ConclusionsSSA with low dose lidocaine may be suitable alternative and competitive for modern GA in ambulatory anorectal surgery

    Nonlinear Channel Estimation Error Effect on Capacity of MIMO System

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    This paper presents the effect of nonlinearity and the effect of estimation error on the channel capacity in MIMO system. We consider a nonlinear MIMO channel, and compare the capacity of Rayleigh MIMO channel model with estimation error with the nonlinear model, at different estimation errors. We consider the estimation error as Gaussian distribution. The simulation results show that the channel capacity of linear and nonlinear MIMO channels are sensitive to the channel estimation error, and due to the nonlinearity, the capacity is less than linear channel. Keywords: MIMO, MIMO Modeling, channel capacity, channel estimation error, nonlinear MIMO channel.

    Effect of Sickle Cell Crises Prevention Guide for Children on Parents Knowledge and Reported Practices

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    Sickle cell anemia (SCA) is a global health concern associated with high childhood morbidity and mortality. The major associated complication is sickle cell crisis which cause frequent hospital admission. Therefore, the purpose of this study was to examine the effect of sickle cell crises prevention guide for children on parents’ knowledge and reported practices. The study was conducted at Hematology &amp; oncology unit of Pediatric department at Menoufia University Hospital and Health insurance hospital for children.  A quazi experimental design was used. A convenient sample of parents with sickle cell children in the above mentioned settings were selected (34 parents) from January to November 2018. One tool was used for data collection consists of 4-sections questionnaire to assess parents' knowledge and practice. The results of this study revealed that there were knowledge deficit between parents' about sickle cell disease, approximately two thirds of parents (64.7%) had improved on post intervention for reported practices of crisis prevention than pre intervention. Also, 79.4% of parents didn’t use social and cultural practices in prevention of sickle cell crises post intervention. Therefore, there was a highly statistical significance differences between pre and post intervention. Conclusion, implementing sickle cell prevention guide improve parents’ knowledge and reported practices for prevention of crises to promote children recovery. Recommendation, ensure that sickle cell booklets are made available to hospitals for parents in order to remind themselves on treatment and prevention of sickle cell crises. Keywords: Sickle cell crisis, knowledge, Practice DOI: 10.7176/JHMN/64-07 Publication date:July 31st 201

    Adjuvant role of corticosteroids in the treatment of community-acquired pneumonia

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    AbstractBackgroundDespite progress in life-support measures and antimicrobial therapy, the mortality of severe pneumonia has not varied since the mid-1990s, suggesting that other factors are of crucial importance in the evolution of this respiratory infection.ObjectiveTo evaluate the impact of hydrocortisone infusion in community-acquired pneumonia (CAP) in the attenuation of systemic inflammation and reduction of sepsis-related complications.MethodsThe study enrolled 80 patients, clinically and radiolodically diagnosed as community-acquired pneumonia, admitted to Chest department, Respiratory Intensive Care Unit, General Medicine Department and General Medicine Intensive Care Unit of Zagazig University Hospitals. Sixty of them were randomized to receive hydrocortisone as a bolus dose of 200mg intravenously once (only at day 1) then 10mg/h IV infusion for 7days and twenty received placebo, along with antibiotics according to IDSA/ATS 2007 guidelines which were given for both groups. The following parameters were compared in both groups; PaO2 and PaO2/FiO2 ratio, length of hospital stay, duration of IV antibiotic treatment, duration of mechanical ventilation, weaning success from mechanical ventilation, pneumonia complication and hospital outcome.ResultsHydrocortisone treated patients showed a significant improvement in PaO2 and PaO2/FiO2 ratio, a significant reduction in White blood cell count, C-reactive protein levels, Erythrocyte sedimentation rate, a significant reduction in the duration of mechanical ventilation, duration of IV antibiotic treatment, pneumonia complications, and length of hospital stay. Also there was an improvement of hospital outcome, weaning success from mechanical ventilation and radiological resolution compared to the placebo group.ConclusionAdjunctive 7day course of low dose hydrocortisone IV in patients with CAP hastens clinical recovery and prevents the development of sepsis-related complications with a significant reduction in the duration of mechanical ventilation, duration of IV antibiotics and length of hospital stay with the improvement in hospital outcome and weaning success from mechanical ventilation

    Calibration and validation of SALTMED model under dry and wet year conditions using chickpea field data from Southern Portugal

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    The SALTMED model is one of the few available generic models that can be used to simulate crop growth with an integrated approach that accounts for water, crop, soil, and field management. It is a physically based model using the well-known water and solute transport, evapotranspiration, and water uptake equations. In this paper, the model simulated chickpea growth under different irrigation regimes and a Mediterranean climate. Five different chickpea varieties were studied under irrigation regimes ranging from rainfed to 100 % crop water requirements, in a dry and a wet year. The calibration of the model using one of the chickpea varieties was sufficient for simulating the other varieties, not requiring a specific calibration for each individual chickpea variety. The results of calibration and validation of the SALTMED model showed that the model can simulate very accurately soil moisture content, grain yield, and total dry biomass of different chickpea varieties, in both wet and dry years. This new version of the SALTMED model (v. 3.02.09) has more features and possibilities than the previous versions, providing academics and professionals with a very good tool to manage water, soil, and crops

    Energy and Momentum Distributions of Kantowski and Sachs Space-time

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    We use the Einstein, Bergmann-Thomson, Landau-Lifshitz and Papapetrou energy-momentum complexes to calculate the energy and momentum distributions of Kantowski and Sachs space-time. We show that the Einstein and Bergmann-Thomson definitions furnish a consistent result for the energy distribution, but the definition of Landau-Lifshitz do not agree with them. We show that a signature switch should affect about everything including energy distribution in the case of Einstein and Papapetrou prescriptions but not in Bergmann-Thomson and Landau-Lifshitz prescriptions.Comment: 12 page

    Deforming glassy polystyrene: Influence of pressure, thermal history, and deformation mode on yielding and hardening

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    The toughness of a polymer glass is determined by the interplay of yielding, strain softening, and strain hardening. Molecular-dynamics simulations of a typical polymer glass, atactic polystyrene, under the influence of active deformation have been carried out to enlighten these processes. It is observed that the dominant interaction for the yield peak is of interchain nature and for the strain hardening of intrachain nature. A connection is made with the microscopic cage-to-cage motion. It is found that the deformation does not lead to complete erasure of the thermal history but that differences persist at large length scales. Also we find that the strain-hardening modulus increases with increasing external pressure. This new observation cannot be explained by current theories such as the one based on the entanglement picture and the inclusion of this effect will lead to an improvement in constitutive modeling

    Energy Distribution of a Stationary Beam of Light

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    Aguirregabiria et al showed that Einstein, Landau and Lifshitz, Papapetrou, and Weinberg energy-momentum complexes coincide for all Kerr-Schild metric. Bringely used their general expression of the Kerr-Schild class and found energy and momentum densities for the Bonnor metric. We obtain these results without using Aguirregabiria et al results and verify that Bringley's results are correct. This also supports Aguirregabiria et al results as well as Cooperstock hypothesis. Further, we obtain the energy distribution of the space-time under consideration.Comment: Latex, no figures [Admin note: substantial overlap with gr-qc/9910015 and hep-th/0308070
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