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In this study, a comparison between the fifth-order model and the third-order model of the Doubly Fed Induction Generator (DFIG) is presented. This paper aims to study and analyze transient stability for the fifth-order and third-order models. The fifth-order model of the DFIG is based on five differentials equations. Neglecting the stator transients from the fifth-order model of the DFIG, we get the third-order. On startup and control of the power system that the third-order model produces better results than the fifth-order model in the transient regime. The performance of the two models on the startup and control of the power system is proved with the simulations (MATLAB/Simulink® software). Keywords: DFIG, Transient stability, Wind energy, Vector control

BackgroundWeekends off antiretroviral therapy (ART) may help engage HIV-1-infected young people facing lifelong treatment. BREATHER showed short cycle therapy (SCT; 5 days on, 2 days off ART) was non-inferior to continuous therapy (CT) over 48 weeks. Planned follow-up was extended to 144 weeks, maintaining original randomisation.MethodsBREATHER was an open-label, non-inferiority trial. Participants aged 8-24yrs with virological suppression on efavirenz-based first-line ART were randomised 1:1, stratified by age and African/non-African sites, to remain on CT or change to SCT. The Kaplan-Meier method was used to estimate the proportion of participants with viral rebound (confirmed VL≥50 copies/mL) under intent-to-treat at 48 weeks (primary outcome), and in extended follow-up at 96, 144, and 192 weeks. SCT participants returned to CT following viral rebound, 3 VL blips or discontinuation of efavirenz.FindingsOf 199 participants (99 SCT, 100 CT), 97 per arm consented to extended follow-up. Median follow-up was 185.3 weeks (IQR 160.9-216.1). 69 (70%) SCT participants remained on SCT at last follow-up. 105 (53%) were male, baseline median age 14 years (IQR 12-18), median CD4 count 735 cells/μL (IQR 576-968). 16 SCT and 16 CT participants had confirmed VL≥50 copies/mL by the end of extended follow-up (HR 1.00, 95% CI 0.50-2.00). Estimated difference in percentage with viral rebound (SCT minus CT) by week 144 was 1.9% (90% CI -6.6-10.4; p = 0.72) and was similar in a per-protocol analysis. There were no significant differences between arms in proportions of participants with grade 3/4 adverse events (18 SCT vs 16 CT participants; p = 0.71) or ART-related adverse events (10 vs 12; p = 0.82). 20 versus 8 serious adverse events (SAEs) were reported in 16 SCT versus 4 CT participants, respectively (p = 0.005 comparing proportions between groups; incidence rate ratio 2.49, 95%CI 0.71-8.66, p = 0.15). 75% of SAEs (15 SCT, 6 CT) were hospitalisations for a wide range of conditions. 3 SCT and 6 CT participants switched to second-line ART following viral failure (p = 0.50).ConclusionsSustainable non-inferiority of virological suppression in young people was shown for SCT versus CT over median 3.6 years. Standard-dose efavirenz-based SCT is a viable option for virologically suppressed HIV-1 infected young people on first-line ART with 3-monthly VL monitoring.Trial registrationEudraCT 2009-012947-40 ISRCTN 97755073 ClinicalTrials.gov NCT01641016.

Nowadays technology became an affective and worthy tool for learning and acquisition of knowledge. Although e-books have many facilities and tools which motivate children to read and develop their reading skills, most of the early childhood institutions in Oman are not using e-books for teaching children. Therefore, this study aims to investigate the difference between using e-books and printed books to motivate kindergarteners to read and enhancing their understanding of the text. This study compares between experimental group which use e-books and control group which use printed books. Findings show that there are no significant differences between the two groups with regard to motivation. However, children who read from paper books got better scores in the comprehension test. The study concludes with some future recommendations.

Item does not contain fulltext BACKGROUND: Excess risks for death/opportunistic disease in adults randomized to CD4-driven planned treatment interruption (PTI) in the Strategies for Management of Antiretroviral Therapy (SMART) trial remained after antiretroviral therapy (ART) re-initiation. Risks for children following PTI were evaluated in long-term follow-up of children in the PENTA 11 trial. METHODS: Children with HIV RNA below 50 copies/ml and CD4 at least 30% (2-6 years) or at least 500 cells/mul (7-15 years) were randomized to continuous ART (cART) or PTI in PENTA 11 (ISRCTN 36694210). After the end of the trial, all were recommended to resume ART. Data were collected annually and analysed up to the second year of visit. RESULTS: One hundred and one (51 cART, 50 PTI; median baseline age 9.2 years) children had median overall follow-up 4.6 (range 3.7-5.0) years. During 2-year post-trial period, there were no deaths or new Centers for Disease Control and Prevention (CDC) stage B/C events. Rate of clinical grade of at least two events was similar between PTI and cART [relative risk (RR) 1.03; 95% confidence interval (CI) 0.43, 2.50; P = 0.94]. At 2 years, difference in absolute CD4% between PTI and cART was -1.6% (-4.5%; 1.3%; P = 0.27), and proportions with HIV RNA below 50 copies/ml were 82 versus 86% (P = 0.57), respectively; no differences in growth or fasting lipids were observed. Key predictors of greater CD4% recovery after re-initiating ART were higher CD4% at baseline (P < 0.001) and longer time since ART re-initiation (P < 0.001). During overall follow-up, 4 (8%) PTI versus 5 (10%) CT children switched ART for failure (P = 0.75) and 9 (18%) versus 1 (2%) (P = 0.008) substituted ART for simplification. CONCLUSIONS: No adverse clinical, immunological or virological consequences of PTI were observed 2 years after the end of PENTA 11 trial. Although ART interruption is not generally recommended, it may be an acceptable option for children, particularly when there is high risk of unplanned treatment interruptions.

Objectives: The objectives of this study were to study the information-seeking behaviour of otolaryngologists in Oman, and their willingness to learn and acquire evidence-based practice (EBP) skills. Methods: A cross-sectional survey was carried out by distribution of a questionnaire to 63 otolaryngologists (ranging from residents to consultants) employed in Oman who attended a national otolaryngology meeting in January 2010. Results: Forty-nine completed questionnaires were received; 57% of the respondents had more than 10 years’ experience, and 60% were from tertiary care; 38.8% “totally agreed”, and 36.7% “partially agreed” that EBP would improve the quality of care and thus provide effective health care to patients. More than 46.9% had 1–5 questions per week, 18.4% had 11 or more questions per week at the point-of-care; 69.4% were willing to acquire information mastery skills. There was a statistical correlation between the number of years of experience, the number of questions, and willingness to acquire information mastery skills. Conclusion: In day-to-day clinical practice, web-based resources are of increasing significance. Most otolaryngologists in Oman not only believed that it is essential to acquire information mastery skills, but also that effective health care depends on such skills and on EBP. Most were willing to acquire these skills. In the future, these skills will be vital in helping otolaryngologists deliver effective health care solutions.

OBJECTIVE: To describe the long-term efficacy over 5 years of regimens including combinations of abacavir, lamivudine and/or zidovudine in previously untreated children in the PENTA 5 trial. DESIGN: PENTA 5 was a 48-week randomised controlled trial comparing three dual nucleoside reverse transcriptase inhibitor (NRTI) combinations as part of first triple antiretroviral therapy (ART). METHODS: 128 ART-naïve children were randomised to zidovudine\lamivudine (n = 36), zidovudine\abacavir (45) or lamivudine\abacavir (47). Asymptomatic children (n = 55) were also randomised to nelfinavir or placebo; all other children received open-label nelfinavir. Analyses are intent-to-treat and adjusted for minor baseline imbalances and receipt of nelfinavir/placebo. RESULTS: Median follow-up was 5.8 years. By 5 years, 17 (47%), 28 (64%) and 18 (39%) children had changed their randomised NRTIs in the zidovudine\lamivudine, zidovudine\abacavir and lamivudine\abacavir groups respectively, but 18%, 50% and 50% of these changes were either early single drug substitutions for toxicity or switches with viral suppression (HIV-1 RNA < 400 copies/ml; e.g. to simplify regimen delivery). At 5 years, 55%/32% zidovudine\lamivudine, 50%/25% zidovudine\abacavir and 79%/63% lamivudine\abacavir had HIV-1 RNA < 400/< 50 copies/ml respectively (p = 0.03/p = 0.003). Mean increase in height-for-age 0.42, 0.68, 1.05 (p = 0.02); weight-for-age 0.03, 0.13, 0.75 (p = 0.02). Reverse transcriptase resistance mutations emerging on therapy differed between the groups: zidovudine\lamivudine (M41L, D67N, K70R, M184V, L210W, T215Y); zidovudine\abacavir (M41L, D67N, K70R, L210W, T215F/Y, K219Q); lamivudine\abacavir (K65R, L74V, Y115F, M184V). CONCLUSIONS: Five year data demonstrate that lamivudine\abacavir is more effective in terms of HIV-1 RNA suppression and growth changes, with lower rates of switching with detectable HIV-1 RNA than zidovudine\lamivudine or zidovudine\abacavir, and should be preferred as first-line NRTI backbone.

BACKGROUND: Quantifying pediatric immunologic recovery by highly active antiretroviral therapy (HAART) initiation at different CD4 percentage (CD4%) and age thresholds may inform decisions about timing of treatment initiation. METHODS: HIV-1-infected, HAART-naive children in Europe and the Americas were followed from 2002 through 2009 in PENPACT-1. Data from 162 vertically infected children, with at least World Health Organization “mild” immunosuppression and CD4% RESULTS: Seventy-two percent of baseline immunosuppressed children recovered to normal within 4 years. Compared with “severe” immunosuppression, more children with “mild” immunosuppression (difference 36%, 95% confidence interval [CI]: 22% to 49%) or “advanced” immunosuppression (difference 20.8%, 95% CI: 5.8% to 35.9%) recovered a normal CD4%. For each 5-year increase in baseline age, the proportion of children achieving a normal CD4% declined by 19% (95% CI: 11% to 27%). Combining baseline CD4% and age effects resulted in >90% recovery when initiating HAART with “mild” immunosuppression at any age or “advanced” immunosuppression at age CONCLUSIONS: Initiating HAART at higher CD4% and younger ages maximizes potential for immunologic recovery. Guidelines should weigh immunologic benefits against long-term risks.

A total of 195 children were randomised to zidovudine (immediate) or matching placebo (deferred) in a multicentre double blind trial in vertically HIV infected children with early disease (the PENTA 1 trial). Median follow up in the blinded phase was 1.9 years. Thereafter, individual children were unblinded following the results of adult trials showing a benefit of combination antiretroviral therapy (ART) over monotherapy, but follow up continued and is reported here until December 1998 (total follow up 4.6 years). Median time to starting ART in the deferred group was 2.7 years; 19% of deferred children had not started ART by 1999. Throughout follow up, the percentage of time spent on no ART, monotherapy, dual, and triple ART was 21%, 44%, 29%, and 6% respectively for immediate and 62%, 12%, 18%, and 8% for deferred groups. During the blinded phase eight (7.8%) immediate and 12 (13.3%) deferred children developed AIDS or died (log rank p = 0.24); overall 21 immediate and 20 deferred children progressed. In an analysis including all children regardless of original allocation, the risk of progression to AIDS or death, adjusting for age and time since trial entry was significantly lower during 1997-98 (2.4 per 100 child years) than during 1992-96 (6.6 per 100 child years), most likely a result of increased use of combination ART.

Contains fulltext : 126098.pdf (Publisher’s version ) (Open Access) OBJECTIVES: To evaluate the immunological and viral consequences of planned treatment interruptions (PTI) in children with HIV. DESIGN: This was an immunological and virological sub-study of the Paediatric European Network for Treatment of AIDS (PENTA) 11 trial, which compared CD4-guided PTI of antiretroviral therapy (ART) with continuous therapy (CT) in children. METHODS: HIV-1 RNA and lymphocyte subsets, including CD4 and CD8 cells, were quantified on fresh samples collected during the study; CD45RA, CD45RO and CD31 subpopulations were evaluated in some centres. For 36 (18 PTI, 18 CT) children, immunophenotyping was performed and cell-associated HIV-1 DNA analysed on stored samples to 48 weeks. RESULTS: In the PTI group, CD4 cell count fell rapidly in the first 12 weeks off ART, with decreases in both naive and memory cells. However, the proportion of CD4 cells expressing CD45RA and CD45RO remained constant in both groups. The increase in CD8 cells in the first 12 weeks off ART in the PTI group was predominantly due to increases in RO-expressing cells. PTI was associated with a rapid and sustained increase in CD4 cells expressing Ki67 and HLA-DR, and increased levels of HIV-1 DNA. CONCLUSIONS: PTI in children is associated with rapid changes in CD4 and CD8 cells, likely due to increased cell turnover and immune activation. However, children off treatment may be able to maintain stable levels of naive CD4 cells, at least in proportion to the memory cell pool, which may in part explain the observed excellent CD4 cell recovery with re-introduction of ART.

Background Once-daily dosing of abacavir and lamivudine has been approved for adults, but paediatric data are insufficient. We conducted a pharmacokinetic study of once-daily and twice-daily abacavir and lamivudine in children aged 3–Methods Children with stable HIV type-1 (HIV-1) RNA levels after 12 weeks treatment with twice-daily abacavir (8 mg/kg) with or without lamivudine (4 mg/kg) underwent plasma pharmacokinetic sampling. Children then switched to once-daily abacavir (16 mg/kg) with or without lamivudine (8 mg/kg), and sampling was repeated 4 weeks later. The area under the plasma concentration– time curve over 24 h (AUC0–24) and the maximum concentration (Cmax) were compared using geometric mean ratios (GMRs); 90% confidence intervals (CIs) within the range of 0.80–1.25 were considered bioequivalent. Results A total of 18 children (4, 6 and 8 in the 3–0–24, once-daily versus twice-daily, was 1.07 (90% CI 0.92–1.23) for abacavir and 0.91 (90% CI 0.79–1.06) for lamivudine. Cmax almost doubled on once-daily versus twice-daily dosing: abacavir and lamivudine GMRs were 2.04 (90% CI 1.73–2.42) and 1.78 (90% CI 1.52–2.09), respectively. At baseline, 12, 24 and 48 weeks, 89%, 94%, 100% and 89% of children had HIV-1 RNAConclusions Bioequivalence was demonstrated on AUC0–24 between twice-daily and once-daily abacavir; very similar AUC0–24 values were seen for twice-daily and once-daily lamivudine. Given that viral load suppression rates were maintained, these data suggest that once-daily abacavir and lamivudine might be an option for children aged 3–

To evaluate clinical, immunological and virological consequences of CD4-guided antiretroviral therapy (ART) planned treatment interruptions (PTIs) compared with continuous therapy in children with chronic HIV infection in the Paediatric European Network for Treatment of AIDS 11 trial.This was a multicentre, 72-week, open, randomized, phase II trial.One hundred and nine children with HIV-RNA below 50 copies/ml and CD4% of at least 30% (2-6 years) or at least 25% and CD4 cell count of at least 500 cells/microl (7-15 years) were randomized to continuous therapy (53) or PTI (56). In PTI, ART was restarted if confirmed CD4% was less than 20% or more than 48 weeks had been spent off ART. The primary outcome was Centers for Disease Control and Prevention (CDC) stage C event, death or CD4% less than 15% (and CD4 cell count less than 200 cells/microl for children aged 7-15 years).At baseline, median (interquartile range) age was 9 (6-12) years, CD4% 37% (33-41), CD4 cell count 966 (793-1258) cells/microl, nadir CD4% before combination ART 18% (10-27), time on ART 6 (3-6) years and 26% were CDC stage C. After median (range) 130 (33-180) weeks of follow-up, 4 versus 48% of time was spent off ART in continuous therapy and PTI, respectively. No child died or had a new CDC stage C event; one (2%) continuous therapy versus four (7%) PTI children had a primary outcome based on CD4%/cell count (P = 0.2). Lower nadir CD4% predicted faster CD4% decline after stopping ART. Younger age and higher nadir CD4% predicted being off ART for at least 48 weeks and better CD4% recovery following PTI.In this first paediatric trial of PTI, there were no serious clinical outcomes. Younger children had better CD4% recovery after PTIs. Immunology substudies and long-term follow-up in Paediatric European Network for Treatment of AIDS 11 trial are ongoing. Further research into the role of treatment interruption in children is required, particularly, as guidelines now recommend early ART for all infected infants.

Contains fulltext : 71467.pdf (Publisher’s version ) (Open Access) BACKGROUND: The optimum strategy for stopping treatment with drugs that have different half-lives in a combination regimen to minimize the risk of selecting drug-resistant viruses remains unknown. We evaluated drug concentrations in plasma, human immunodeficiency virus (HIV) load, and development of drug resistance after a planned treatment interruption of a nonnucleoside reverse-transcriptase inhibitor (NNRTI)-containing regimen in HIV type 1-infected children. METHODS: Children with viral loads or =30% (for children aged 2-6 years) or CD4 cell percentages > or =25% and CD4 cell counts > or =500 cells/microL (for children aged 7-15 years) were randomized to either a planned treatment interruption or to continuous therapy. In the planned treatment interruption arm, either (1) treatment with nevirapine or efavirenz was stopped, and treatment with the remaining drugs was continued for 7-14 days, or (2) nevirapine or efavirenz were replaced by a protease inhibitor, and all drugs were stopped after 7-14 days. Sampling for determination of plasma drug concentrations, measurement of viral load, and drug resistance testing was scheduled at day 0, day 7 (drug concentrations only), day 14, and day 28 after interruption of treatment with an NNRTI. RESULTS: Treatment with an NNRTI was interrupted for 35 children (20 were receiving nevirapine, and 15 were receiving efavirenz). Median time from NNRTI cessation to stopping all drugs was 9 days (range, 6-15 days) for nevirapine and 14 days (range, 6-18 days) for efavirenz. At 7 days, 1 (5%) of 19 and 4 (50%) of 8 children had detectable nevirapine and efavirenz concentrations, respectively; efavirenz remained detectable in 3 (25%) of 12 children at 14 days. At 14 days, viral load was > or =50 copies/mL in 6 of 16 children interrupting treatment with nevirapine (range, 52-7000 copies/mL) and in 2 of 12 children interrupting treatment with efavirenz (range, 120-1600 copies/mL). No new NNRTI mutations were observed. CONCLUSIONS: In children with virological suppression who experienced interruption of treatment with an NNRTI, staggered or replacement stopping strategies for a median of 9 days for nevirapine and 14 days for efavirenz were not associated with the selection of NNRTI resistance mutations.

Contains fulltext : 49547.pdf (Publisher’s version ) (Closed access)

In the information sciences such as computer science, telecommunications, the treatment of signal or image transmission, the field effect components play an important role. In the frame of our work, we are interested in the study of the gallium arsenide short gate field effect transistor called GaAs MESFET. After analytical studying the component static characteristics, according to different operation regimes, a numerical simulation was worked out. The influence of technological dimensions (L, Z, a, and Nd) was studied. The obtained results allow us to determine optimal parameters of the devices from the viewpoint of their applications and specific use.

Two new structures of active inductance which implement MESFET transistors are proposed in this article. The technological parameters of the components of “inductances” are those of 0.8 µm MESFET technology. We expose the advantages of these new structures such as the adjustable character of the value of the active inductance like their limitation, and we compare them to those of the literature.

This paper describes the polarization effect of the substrate on the electric characteristics of the GaAs Metal Semiconductor Field Effect Transistor (GaAs MESFET). An analysis based on the existence of a double space charge at the interface active layer – semi-insulating substrate is applied to determine the active layer and interface parameters. The properties of the drain current and the output admittance characteristics as well as the physical phenomena inherent to this interface are assigned to the dynamic response of the double space charge region.

In resent years a considerable effort (experience, numerical simulation and theoretical prediction models) has been devoted to the study of photovoltaic devices characterised by high efficiency and low cost. The present study comes in way to contribute in the optimisation of the performance of Si an GaAs based (N/P) solar cells by the determination of physical and technological parameters giving the best photovoltaic conversion efficiency and a good spectral response. The four principal parameters that influence the operation of a solar cell are emitter and base doping, junction depth and base thickness. We have also taken into account the recent technique of elaboration of these structures. This study concerns the use of novel optimised values of electronic properties of GaAs and Si materials such as recombination velocity at surface (front and back). All enhancements recently reached: BSF, BSR layers, ARC anti reflection layer with textured surface, surfaces passivation, improved ohmic contacts are taken into account. I-V, P-V, EQE-λ characteristics obtained by PC1D similator on two different cells (Si and GaAs) under the global spectra AM1.5 have allowed us to get optimal cells. The comparison of the cells shows the advantage of given GaAs cells. The effect of solar concentration (1-100 suns) on cell operation has been studied. The later has contributed to the enhancement of the energetic efficiency. The effects different standard spetra such as AM1, AM1, 5G, and AM1.5D have been studied. The optimal values of physical parameters giving the best currents of short-circuit and voltages of open circuit as well as high conversion efficiency have been obtained for these two solar materials.

New nonlinear model for simulating physical and geometrical parameters to determine the junctions capacities of "the Gallium Arsenide Metal Semiconductor Field Effect Transistor" GaAs MESFET are represented in this paper. Non linear variations of the bias and gate-source and gate-drain capacities have been found. A simulated values show excellent agreement with experimental results.

Introduction Treatment options for children with HIV-1 are limited. We aimed to compare activity and safety of three dual-nucleoside analogue reverse-transcriptase inhibitor (NRTI) regimens with or without a protease inhibitor in previously untreated children with HIV-1.Methods In our multicentre trial, we randomly assigned 36 children to zidovudine and lamivudine, 45 to zidovudine and abacavir, and 47 to lamivudine and abacavir. Children who were symptomfree (n=55) were also randomly assigned to receive nelfinavir or placebo. Children with more advanced disease received open-label nelfinavir (73). Primary endpoints were change in plasma HIV-1 RNA at 24 and 48 weeks for the NRTI comparison and occurrence of serious adverse events for both randomised comparisons. Analyses were by intention to treat.Findings Children had a median CD4 percentage of 22% (IQR 15-29) and a mean HIV-1 RNA concentration of 5.0 log copies/mL (SD 0.8). One child was lost to follow-up and one died of sepsis. At 48 weeks, in the zidovudine/lamivudine, zidovudine/abacavir, and lamivudine/abacavir groups, mean HIV-1 RNA had decreased by 1.71, 2.19, and 2.63 log copies/mL, respectively (estimated in absence of nelfinavir) (P=0.02 after adjustment for baseline factors). One child had a hypersensitivity reaction to abacavir; and three with possible reactions stopped abacavir. There were 24 serious adverse events-six in the symptom-free children (all on nelfinavir), but none were attributed to nelfinavir.Interpretation Regimens containing abacavir were more effective than zidovudine/lamivudine. Such regimens could be combined with protease inhibitors and non-nucleoside reverse transcriptase inhibitors for safe and effective treatment of previously untreated children with HIV-1.