Impact of Automatic Circuit Reclosers and Distributed Generators on the Reliability Indices of Electrical Distribution Systems

Reliability is the ability of power system to perform its intended function as at when due. Parameters used to assess the level at which this is done are called reliability indices. Previous researches have not focused deeply on the effect of installing automatic circuit reclosers ACRs and distributed generators (DGs) on the assessment of reliability indices of electrical power distribution system, hence, the drive towards this research paper. Monte Carlo Simulation (MCS) was performed in MATLAB on the IEEE 34 test feeder. Under three different case studies- when one ACF was installed on the test system, when two ACRs were installed on the test system and when 1MW DG unit was installed on the test system.  Real system data were used as input parameters for the simulation. The overall distribution system reliability was evaluated using the load point and the system reliability indices such as System Average Interruption Frequency Index (SAIFI), System Average Interruption Duration Index (SAIDI) and Customer Average Interruption Duration Index (CAIDI).  (CAIDI), Average Service Availability Index (ASAI) and EUE.The results obtained with the MCS were compared with the results obtained previously for the same test system using analytical approach and was found to be in agreement. The results of the research paper showed that the installation of an automatic circuit recloser gave a reduction in SAIFI value from 17.33hours/year to 14.93 hours/year with the installation of ACR between nodes (800-802). The best improvement was noticed when ACR was installed between nodes (834-842) in the electrical feeder. The value of SAIDI obtained also decreased from 8.90hom/year to 7.99 hours/year with the installation ACR between nodes (800-802). When two ACR were installed in the test system between nodes (828-824) and (824-826), the values obtained for SAIFI were 10.74 hours/year and 11.20 hours/year respectively representing a level of improvement in the SAIFI index. Between these nodes, values of SAIFI were also 4.211 hours/year and 4.423 hours/year which also represents an improvement in SAIDI values.Installation of 1MW Distributed generator (DG) unit in the test system gave SAIFI and SAIDI values of 14.23 hours/year and 5.80 hours/year respectively representing an improvement in there two indices compared to when ACRs were installed at anywhere in the test system. The values obtained for ASAI for different locations of the 1MW DG unit fluctuate throughout the case descriptions. With the installation of the 1MW DG unit between nodes 834-842, 844-846, 834-860, 836-840, and 862-838, the values obtained for ASAI were 5.196, 5.101, 5.012, 6.141 and 6.128 respectively which represent appreciable level of improvement as compared to the base case. With the installation of one DG in the test system, the value obtained for the EUE was 17709kw. With the additional installation of ACR between nodes (846-848), (862-832), (888-890) and (854-856), the values obtained for EUE were 1152 kW, 11926 kW, 13146  kW and 14191 kW respectively indicating a level of reductions in the values of EUE. The ACRs, once installed optimally on the test system improves the reliability of the distribution system by isolating the healthy parts of the system automatically, which maintains the service to a substantial number of customers and reduce the repair time. The integration of DGs into the distribution test system provides the opportunity of operating the distribution system as a microgrid, allowing continuity of service in the network. It also forms a useful basis for evaluating the reliability of distribution feeders. Keywords: Automate circuit reclosers (ACRs), Distributed generators (DG), Reliability indices, Monte Carlo Simulation Power Distribution systems, SAIFI, SAIDI, CAIDI, ASAI

Perception of Travel Agents Towards Amadeus And Galileo Global Distribution System

This study was conducted to assess the perception of travel agents towards Amadeus and Galileo Global Distribution System in some selected travel agencies in Lagos Island, Lagos state. Two hundred and forty-three (243) questionnaires were administered while two hundred and seven (207) were retrieved. The first hypothesis was tested using Pearson chi-square value which was less than 0.05 (p=0.000) thereby rejecting the null hypothesis which implies that there is a significant relationship between using Global Distribution System and Travel agencies. Result also reveals that the Pearson chi-square value of the second hypothesis is less than 0.05 (p=0.000) thereby rejecting the null hypothesis which implies that Global Distribution System contributes to the development of travel agencies. Therefore, Global Distribution System helps in the development of travel agencies. Other findings are; Amadeus Global Distribution System is used more than its counterpart Galileo Global Distribution System. Also, Global Distribution System has helped broaden staff knowledge towards reservation and hotel bookings. Based on these findings, it is hereby concluded that Global Distribution System Amadeus is quite prevalent and more used among the agents working with airlines; Global Distribution System Amadeus assumes the foremost position in relation to Galileo Global Distribution Systems, primarily due to the evolution of software that is tailored specially to meet the desires of individual users, allowing the availability and exchange of quality information to enormous number of users, thus linking tourism related companies in the global networks.

Neuronal alterations in the prefrontal cortex of rats with carbon tetrachloride (CCl4) induced hepatic damage

In cirrhosis, some toxic substances accumulate in the brain and modify its functional integrity. In this study, we investigate the impacts of liver damage on the neuronal profile of the prefrontal cortex (PFC) in a rat model of hepatic damage induced with carbon tetrachloride (CCl4). This study also evaluated the possible role of liver dysfunction in the etiology of neurodegenerative characteristics associated with the PFC. Ten male Wistar rats weighing 120 to 190 g body weight were used for this study. The rats were divided into 2 groups (A and B) of 5 rats each. The rats in group A (control group) were treated with phosphate buffered saline (PBS) solution only while the rats in group B (treatment group) were treated with carbon tetrachloride (CCl4). The prefrontal cortices of the rats were excised from skulls of the rats, fixed in formol calcium, while the livers were excised from the abdomen of the rats and were fixed in formol saline for cytoarchitectural study using Cresyl fast violet and hematoxylin and eosin stains respectively. The main neuropathological findings observed in this study include cortical necrosis, uneven neuronal loss with varying range of vacuolations in the prefrontal cortices of the CCl4 treated rats when compared with the PBS treated rats. It was observed that the administration of CCl4 induces changes in hepatocellular morphology of the treated rats and these include moderate vascular congestion and extensive cytoplasmic damage in the hepatocytes. These results could be due to loss of hepatic functions

Lung penetration, bronchopulmonary pharmacokinetic/pharmacodynamic profile and safety of 3 g of ceftolozane/tazobactam administered to ventilated, critically ill patients with pneumonia

Objectives: Ceftolozane/tazobactam is approved for hospital-acquired/ventilator-associated bacterial pneumonia at double the dose (i.e. 2 g/1 g) recommended for other indications. We evaluated the bronchopulmonary pharmacokinetic/pharmacodynamic profile of this 3 g ceftolozane/tazobactam regimen in ventilated pneumonia patients. Methods: This was an open-label, multicentre, Phase 1 trial (clinicaltrials.gov: NCT02387372). Mechanically ventilated patients with proven/suspected pneumonia received four to six doses of 3 g of ceftolozane/tazobactam (adjusted for renal function) q8h. Serial plasma samples were collected after the first and last doses. One bronchoalveolar lavage sample per patient was collected at 1, 2, 4, 6 or 8 h after the last dose and epithelial lining fluid (ELF) drug concentrations were determined. Pharmacokinetic parameters were estimated by noncompartmental analysis and pharmacodynamic analyses were conducted to graphically evaluate achievement of target exposures (plasma and ELF ceftolozane concentrations >4 mg/L and tazobactam concentrations >1 mg/L; target in plasma: similar to 30% and similar to 20% of the dosing interval, respectively). Results: Twenty-six patients received four to six doses of study drug; 22 were included in the ELF analyses. Ceftolozane and tazobactam T-max (6 and 2 h, respectively) were delayed in ELF compared with plasma (1h). Lung penetration, expressed as the ratio of mean drug exposure (AUC) in ELF to plasma, was 50% (ceftolozane) and 62% (tazobactam). Mean ceftolozane and tazobactam ELF concentrations remained >4 mg/L and >1mg/L, respectively, for 100% of the dosing interval. Therewere no deaths or adverse event-related study discontinuations. Conclusions: In ventilated pneumonia patients, 3 g of ceftolozane/tazobactam q8h yielded ELF exposures considered adequate to cover ceftolozane/tazobactam-susceptible respiratory pathogens

Global fertility in 204 countries and territories, 1950–2021, with forecasts to 2100:a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BackgroundAccurate assessments of current and future fertility—including overall trends and changing population age structures across countries and regions—are essential to help plan for the profound social, economic, environmental, and geopolitical challenges that these changes will bring. Estimates and projections of fertility are necessary to inform policies involving resource and health-care needs, labour supply, education, gender equality, and family planning and support. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 produced up-to-date and comprehensive demographic assessments of key fertility indicators at global, regional, and national levels from 1950 to 2021 and forecast fertility metrics to 2100 based on a reference scenario and key policy-dependent alternative scenarios.MethodsTo estimate fertility indicators from 1950 to 2021, mixed-effects regression models and spatiotemporal Gaussian process regression were used to synthesise data from 8709 country-years of vital and sample registrations, 1455 surveys and censuses, and 150 other sources, and to generate age-specific fertility rates (ASFRs) for 5-year age groups from age 10 years to 54 years. ASFRs were summed across age groups to produce estimates of total fertility rate (TFR). Livebirths were calculated by multiplying ASFR and age-specific female population, then summing across ages 10–54 years. To forecast future fertility up to 2100, our Institute for Health Metrics and Evaluation (IHME) forecasting model was based on projections of completed cohort fertility at age 50 years (CCF50; the average number of children born over time to females from a specified birth cohort), which yields more stable and accurate measures of fertility than directly modelling TFR. CCF50 was modelled using an ensemble approach in which three sub-models (with two, three, and four covariates variously consisting of female educational attainment, contraceptive met need, population density in habitable areas, and under-5 mortality) were given equal weights, and analyses were conducted utilising the MR-BRT (meta-regression—Bayesian, regularised, trimmed) tool. To capture time-series trends in CCF50 not explained by these covariates, we used a first-order autoregressive model on the residual term. CCF50 as a proportion of each 5-year ASFR was predicted using a linear mixed-effects model with fixed-effects covariates (female educational attainment and contraceptive met need) and random intercepts for geographical regions. Projected TFRs were then computed for each calendar year as the sum of single-year ASFRs across age groups. The reference forecast is our estimate of the most likely fertility future given the model, past fertility, forecasts of covariates, and historical relationships between covariates and fertility. We additionally produced forecasts for multiple alternative scenarios in each location: the UN Sustainable Development Goal (SDG) for education is achieved by 2030; the contraceptive met need SDG is achieved by 2030; pro-natal policies are enacted to create supportive environments for those who give birth; and the previous three scenarios combined. Uncertainty from past data inputs and model estimation was propagated throughout analyses by taking 1000 draws for past and present fertility estimates and 500 draws for future forecasts from the estimated distribution for each metric, with 95% uncertainty intervals (UIs) given as the 2·5 and 97·5 percentiles of the draws. To evaluate the forecasting performance of our model and others, we computed skill values—a metric assessing gain in forecasting accuracy—by comparing predicted versus observed ASFRs from the past 15 years (2007–21). A positive skill metric indicates that the model being evaluated performs better than the baseline model (here, a simplified model holding 2007 values constant in the future), and a negative metric indicates that the evaluated model performs worse than baseline.FindingsDuring the period from 1950 to 2021, global TFR more than halved, from 4·84 (95% UI 4·63–5·06) to 2·23 (2·09–2·38). Global annual livebirths peaked in 2016 at 142 million (95% UI 137–147), declining to 129 million (121–138) in 2021. Fertility rates declined in all countries and territories since 1950, with TFR remaining above 2·1—canonically considered replacement-level fertility—in 94 (46·1%) countries and territories in 2021. This included 44 of 46 countries in sub-Saharan Africa, which was the super-region with the largest share of livebirths in 2021 (29·2% [28·7–29·6]). 47 countries and territories in which lowest estimated fertility between 1950 and 2021 was below replacement experienced one or more subsequent years with higher fertility; only three of these locations rebounded above replacement levels. Future fertility rates were projected to continue to decline worldwide, reaching a global TFR of 1·83 (1·59–2·08) in 2050 and 1·59 (1·25–1·96) in 2100 under the reference scenario. The number of countries and territories with fertility rates remaining above replacement was forecast to be 49 (24·0%) in 2050 and only six (2·9%) in 2100, with three of these six countries included in the 2021 World Bank-defined low-income group, all located in the GBD super-region of sub-Saharan Africa. The proportion of livebirths occurring in sub-Saharan Africa was forecast to increase to more than half of the world's livebirths in 2100, to 41·3% (39·6–43·1) in 2050 and 54·3% (47·1–59·5) in 2100. The share of livebirths was projected to decline between 2021 and 2100 in most of the six other super-regions—decreasing, for example, in south Asia from 24·8% (23·7–25·8) in 2021 to 16·7% (14·3–19·1) in 2050 and 7·1% (4·4–10·1) in 2100—but was forecast to increase modestly in the north Africa and Middle East and high-income super-regions. Forecast estimates for the alternative combined scenario suggest that meeting SDG targets for education and contraceptive met need, as well as implementing pro-natal policies, would result in global TFRs of 1·65 (1·40–1·92) in 2050 and 1·62 (1·35–1·95) in 2100. The forecasting skill metric values for the IHME model were positive across all age groups, indicating that the model is better than the constant prediction.InterpretationFertility is declining globally, with rates in more than half of all countries and territories in 2021 below replacement level. Trends since 2000 show considerable heterogeneity in the steepness of declines, and only a small number of countries experienced even a slight fertility rebound after their lowest observed rate, with none reaching replacement level. Additionally, the distribution of livebirths across the globe is shifting, with a greater proportion occurring in the lowest-income countries. Future fertility rates will continue to decline worldwide and will remain low even under successful implementation of pro-natal policies. These changes will have far-reaching economic and societal consequences due to ageing populations and declining workforces in higher-income countries, combined with an increasing share of livebirths among the already poorest regions of the world.FundingBill & Melinda Gates Foundation

Severe Renal Impairment Has Minimal Impact on Doravirine Pharmacokinetics

Doravirine is a novel nonnucleoside reverse transcriptase inhibitor in development for use with other antiretroviral therapies to treat human immunodeficiency virus type 1 (HIV-1) infection. Doravirine metabolism predominantly occurs via cytochrome P450 3A with <10% of elimination occurring via the renal pathway. Doravirine is a novel nonnucleoside reverse transcriptase inhibitor in development for use with other antiretroviral therapies to treat human immunodeficiency virus type 1 (HIV-1) infection. Doravirine metabolism predominantly occurs via cytochrome P450 3A with <10% of elimination occurring via the renal pathway. As severe renal impairment can alter the pharmacokinetics (PK) of metabolically eliminated drugs, the effect of severe renal impairment on doravirine PK was assessed. A single dose of doravirine 100 mg was administered to subjects aged 18 to 75 years with an estimated glomerular filtration rate (eGFR) of <30 ml/min/1.73 m 2 (severe renal impairment group) and healthy controls with an eGFR of ≥80 ml/min/1.73 m 2 , matched to the mean of the renal impairment group by age (±10 years) and weight (±10 kg). Doravirine plasma concentrations were determined at regular intervals, and safety was monitored throughout. The geometric mean ratios (90% confidence interval) for severe renal impairment/healthy subjects were 1.43 (1.00, 2.04), 1.38 (0.99, 1.92), and 0.83 (0.61, 1.15) for the plasma doravirine area under the curve from zero to infinity (AUC 0–∞ ), plasma concentration at 24 h postdose ( C 24 ), and maximum plasma concentration ( C max ), respectively. Doravirine was generally well tolerated in both groups. Based on the overall efficacy, safety, and PK profile of doravirine, the minor effect of severe renal impairment on doravirine PK observed in this study is not considered clinically meaningful. (This study has been registered at ClinicalTrials.gov under identifier NCT02641067.

Pharmacokinetic profile of ABELCET (amphotericin B lipid complex injection): Combined experience from phase I and phase II studies

SCOPUS: ar.jinfo:eu-repo/semantics/publishe