Effect of AVR and PSS on Power System Transient Stability with Different Wind Generation Technologies

In the last decade, wind generation has been the fastest growing energy source globally. However, higher penetration of wind energy into existing power networks raises concern for power system operators and regulators. In this paper, we investigate the effect of wind farms employing doubly-fed induction generators (DFIGs) on the transient stability of power systems. We carried out simulations to demonstrate and compare the transient performance of the standard 3-machine 9-bus system with and without wind power integration during a fault. We analyzed the generator technology mentioned, replacing one synchronous generator in the system. We also analyzed the mentioned system after introducing the automatic voltage regulators (AVR) and power system stabilizers (PSS) into the system. We simulated the system using DIgSILENT PowerFactory. Our results show that a better transient performance is achieved with the inclusion of DFIGs in the system. There is also a further improvement of the transient stability after including both the AVR and PSS in the simulations. Keywords: Squirrel cage induction generators, Doubly-fed induction generators, Transient stability, Automatic Voltage Regulator, Power System Stabilizer

Cooperative Learning Method and Development of Pre-School Children’s Competences Acquisition in Mathematical Concepts in Kirinyaga County, Kenya

The research from which this paper is derived explored the effect of cooperative learning method on development of pre-schoolers’ competences in mathematical concepts. 20 pre-school teachers on their regular teaching in their pre-schools were observed teaching their 639 Pre-primary Two learners. The purpose of this study was to establish the difference between the mean score index of pre-school learners taught by a teacher who facilitates learning using the Cooperative Learning Method (CLM) and those taught by a teacher who does not. Data was collected through the use of observation schedule and teacher questionnaire. Each of the twenty pre-school teachers was observed by the researcher while facilitating mathematical concepts’ competences during number work lessons. A documentary analysis guide was used to access the pre-school teachers’ schemes of work and lesson plans to establish their level of preparation in line with CLM. Descriptive and inferential statistics were used to analyse the collected data and guided by the themes arising from the objective of the study the key findings were arrived at. The various levels of the teachers’ facilitation of CLM were tied to the pre-school leaners’ performance in the mathematical concepts competences achievement test. The findings emerging showed that those learners who were taught using CLM achieved higher mean score indices than those who were not. The implication here is that the use of CLM improves pre-school learners’ levels of achievement, indicating that it is a more effective method of teaching. Teachers’ facilitation of CLM seemed to have a significant positive influence on the learners’ Mathematical Concepts Competences Acquisition. These features were; availability of groupings and teacher preparedness, level of provision of learning resources, level of coordination, level of interaction, time taken in CLM activities. This implies that CLM imparts the required mathematical concepts competences better than traditional instructional methods. The study recommends that the Ministry of Education should develop programmes and policies that provide regular in-service training, in which CLM training forms a key part of the agenda and to refresh the mathematical concepts competences instructional skills of pre-school teachers. Keywords: Competences; Cooperative Learning Method; Mathematical Concepts DOI: 10.7176/JEP/12-32-05 Publication date: November 30th 202

Quality of care for the treatment for uncomplicated malaria in South-East Nigeria: how important is socioeconomic status?

Introduction: Ensuring equitable coverage of appropriate malaria treatment remains a high priority for the Nigerian government. This study examines the health seeking behaviour, patient-provider interaction and quality of care received by febrile patients of different socio-economic status (SES) groups. Methods: A total of 1642 febrile patients and caregivers exiting public health centres, pharmacies and patent medicine dealers were surveyed in Enugu state, South-East Nigeria to obtain information on treatment seeking behaviour, patient-provider interactions and treatment received. Socioeconomic status was estimated for each patient using exit survey data on household assets in combination with asset ownership data from the 2008 Nigeria Demographic and Health Survey. Results: Among the poorest SES group, 29% sought treatment at public health centres, 13% at pharmacies and 58% at patent medicine dealers (p < 0.01). Very few of those in the richest SES group used public health centres (4%) instead choosing to go to pharmacies (44%) and patent medicine dealers (52%, p < 0.001). During consultations with a healthcare provider, the poorest compared to the richest were significantly more likely to discuss symptoms with the provider, be physically examined and rely on providers for diagnosis and treatment rather than request a specific medicine. Those from the poorest SES group were however, least likely to request or to receive an antimalarial (p < 0.001). The use of artemisinin combination therapy (ACT), the recommended treatment for uncomplicated malaria, was low across all SES groups. Conclusions: The quality of malaria treatment is sub-optimal for all febrile patients. Having greater interaction with the provider also did not translate to better quality care for the poor. The poor face a number of significant barriers to accessing quality treatment especially in relation to treatment seeking behaviour and type of treatment received. Strategies to address these inequities are fundamental to achieving universal coverage of effective malaria treatment and ensuring that the most vulnerable people are not left behind

Intrapartum Antibiotic Chemoprophylaxis Policies for the Prevention of Group B Streptococcal Disease Worldwide: Systematic Review.

Background: Intrapartum antibiotic chemoprophylaxis (IAP) prevents most early-onset group B streptococcal (GBS) disease. However, there is no description of how IAP is used around the world. This article is the sixth in a series estimating the burden of GBS disease. Here we aimed to review GBS screening policies and IAP implementation worldwide. Methods: We identified data through (1) systematic literature reviews (PubMed/Medline, Embase, Literature in the Health Sciences in Latin America and the Caribbean [LILACS], World Health Organization library database [WHOLIS], and Scopus) and unpublished data from professional societies and (2) an online survey and searches of policies from medical societies and professionals. We included data on whether an IAP policy was in use, and if so whether it was based on microbiological or clinical risk factors and how these were applied, as well as the estimated coverage (percentage of women receiving IAP where indicated). Results: We received policy information from 95 of 195 (49%) countries. Of these, 60 of 95 (63%) had an IAP policy; 35 of 60 (58%) used microbiological screening, 25 of 60 (42%) used clinical risk factors. Two of 15 (13%) low-income, 4 of 16 (25%) lower-middle-income, 14 of 20 (70%) upper-middle-income, and 40 of 44 (91%) high-income countries had any IAP policy. The remaining 35 of 95 (37%) had no national policy (25/33 from low-income and lower-middle-income countries). Coverage varied considerably; for microbiological screening, median coverage was 80% (range, 20%-95%); for clinical risk factor-based screening, coverage was 29% (range, 10%-50%). Although there were differences in the microbiological screening methods employed, the individual clinical risk factors used were similar. Conclusions: There is considerable heterogeneity in IAP screening policies and coverage worldwide. Alternative global strategies, such as maternal vaccination, are needed to enhance the scope of global prevention of GBS disease

Global, regional, and national incidence, prevalence, and mortality of HIV, 1980–2017, and forecasts to 2030, for 195 countries and territories: a systematic analysis for the Global Burden of Diseases, Injuries, and Risk Factors Study 2017

Background Understanding the patterns of HIV/AIDS epidemics is crucial to tracking and monitoring the progress of prevention and control efforts in countries. We provide a comprehensive assessment of the levels and trends of HIV/AIDS incidence, prevalence, mortality, and coverage of antiretroviral therapy (ART) for 1980–2017 and forecast these estimates to 2030 for 195 countries and territories. Methods We determined a modelling strategy for each country on the basis of the availability and quality of data. For countries and territories with data from population-based seroprevalence surveys or antenatal care clinics, we estimated prevalence and incidence using an open-source version of the Estimation and Projection Package—a natural history model originally developed by the UNAIDS Reference Group on Estimates, Modelling, and Projections. For countries with cause-specific vital registration data, we corrected data for garbage coding (ie, deaths coded to an intermediate, immediate, or poorly defined cause) and HIV misclassification. We developed a process of cohort incidence bias adjustment to use information on survival and deaths recorded in vital registration to back-calculate HIV incidence. For countries without any representative data on HIV, we produced incidence estimates by pulling information from observed bias in the geographical region. We used a re-coded version of the Spectrum model (a cohort component model that uses rates of disease progression and HIV mortality on and off ART) to produce age-sex-specific incidence, prevalence, and mortality, and treatment coverage results for all countries, and forecast these measures to 2030 using Spectrum with inputs that were extended on the basis of past trends in treatment scale-up and new infections. Findings Global HIV mortality peaked in 2006 with 1·95 million deaths (95% uncertainty interval 1·87–2·04) and has since decreased to 0·95 million deaths (0·91–1·01) in 2017. New cases of HIV globally peaked in 1999 (3·16 million, 2·79–3·67) and since then have gradually decreased to 1·94 million (1·63–2·29) in 2017. These trends, along with ART scale-up, have globally resulted in increased prevalence, with 36·8 million (34·8–39·2) people living with HIV in 2017. Prevalence of HIV was highest in southern sub-Saharan Africa in 2017, and countries in the region had ART coverage ranging from 65·7% in Lesotho to 85·7% in eSwatini. Our forecasts showed that 54 countries will meet the UNAIDS target of 81% ART coverage by 2020 and 12 countries are on track to meet 90% ART coverage by 2030. Forecasted results estimate that few countries will meet the UNAIDS 2020 and 2030 mortality and incidence targets. Interpretation Despite progress in reducing HIV-related mortality over the past decade, slow decreases in incidence, combined with the current context of stagnated funding for related interventions, mean that many countries are not on track to reach the 2020 and 2030 global targets for reduction in incidence and mortality. With a growing population of people living with HIV, it will continue to be a major threat to public health for years to come. The pace of progress needs to be hastened by continuing to expand access to ART and increasing investments in proven HIV prevention initiatives that can be scaled up to have population-level impact

The role of gender on malaria preventive behaviour among rural households in Kenya

Malaria remains a major health and development challenge in the sub-Saharan African economies including Kenya, yet it can be prevented. Technologies to prevent malaria are available but are not universally adopted by male- and female-headed households. The study thus, examined the role of gender in malaria prevention, examining adoption behaviour between male- and female-headed households in Kenya

The global distribution of special needs dentistry across dental school curricula

Introduction: Special needs dentistry (SND) is an emerging dental specialty, with ongoing developments in education and clinical practice focused towards the tailored management of individuals with special needs (SN). Patients with SN have a higher prevalence of oral diseases and unmet dental needs compared to the general population. Although inadequate training and experience in managing patients with SN has been highlighted as a significant barrier to accessing care, there is limited data about the extent of SND teaching at the entry-to-practice or higher levels. Methods: This work is the first to map SND curricula globally, across 180 countries and 1265 dental schools. Results: Although 74.62% of dental schools were found in developing economies, the distribution of programs that reported SND in their courses was highly skewed towards developed countries. In terms of advanced degrees, beyond basic entry-to-practice training, the USA delivered 60% of the SND programs, followed by Canada (15.56%), UK (13.33%), and Australia (8.89%). The term SND appeared in 33.95% of entry-to-practice level program curricula and was less commonly used in transitioning economies. Only 112 SND-specialized practitioners enter the workforce globally each year from developed economies, and all but three advanced degrees are found in G7 countries. Conclusion: By exploring the impact of economic status on its distribution, this paper highlighted the lack of SND representation in dental curricula, especially amongst programs in transitioning or developing economies. Education of both general dentists and specialists is critical as a collaborative effort is needed to manage the growing population of patients with SN

Enhancing carbon sequestration in soil with coal combustion products: a technology for minimising carbon footprints in coal-power generation and agriculture

Coal-fired power generation and agriculture account for more than half of global greenhouse gas emissions, but the coal fly ash (CFA) produced in the former can be a resource for reducing emissions from agriculture to minimise environmental footprints in both industries. Our aim in this study was to test how acidic and alkaline CFA addition could minimise loss of C and N from acidic soil, with or without added manure. We determined composition and structural characteristics of acidic and alkaline CFA for their capacity to adsorb organic carbon, but observed poor adsorption because of low concentrations of cenospheres and unburnt carbon as the primary absorbents in the ash. Addition of CFA had no impact on the loss of carbon or nitrogen from unmanured soil in which concentrations of these nutrients were low. Loss of carbon from manured soil was reduced by 36% with alkaline ashes and by 3-fold with acidic ashes; while loss of N was 30–50% lower with acidic ashes, but 28% higher with alkaline ashes, compared with no ash treatment. The increases in C sparing with CFA addition were achieved not by direct C absorption but by restraining microbial population and respiration, and potentially emissions. Alkaline CFA increased soil pH and if used to substitute just 10% of lime for ameliorating soil acidity would reduce CO2 emission associated with the mining of the lime and its eventual dissolution in soil by ~ 2.66 Tg or 2.8% of Australia’s annual agricultural emissions. High concentrations of oxides of phosphorus, silicon, titanium and clay particles in acidic ashes, and oxides of cations in alkaline ashes, were associated with potential for promoting C storage and acidity amelioration in soil

Plasma miRNA as Biomarkers for Assessment of Total-Body Radiation Exposure Dosimetry

The risk of radiation exposure, due to accidental or malicious release of ionizing radiation, is a major public health concern. Biomarkers that can rapidly identify severely-irradiated individuals requiring prompt medical treatment in mass-casualty incidents are urgently needed. Stable blood or plasma-based biomarkers are attractive because of the ease for sample collection. We tested the hypothesis that plasma miRNA expression profiles can accurately reflect prior radiation exposure. We demonstrated using a murine model that plasma miRNA expression signatures could distinguish mice that received total body irradiation doses of 0.5 Gy, 2 Gy, and 10 Gy (at 6 h or 24 h post radiation) with accuracy, sensitivity, and specificity of above 90%. Taken together, these data demonstrate that plasma miRNA profiles can be highly predictive of different levels of radiation exposure. Thus, plasma-based biomarkers can be used to assess radiation exposure after mass-casualty incidents, and it may provide a valuable tool in developing and implementing effective countermeasures

Health sector spending and spending on HIV/AIDS, tuberculosis, and malaria, and development assistance for health: progress towards Sustainable Development Goal 3

Sustainable Development Goal (SDG) 3 aims to “ensure healthy lives and promote well-being for all at all ages”. While a substantial effort has been made to quantify progress towards SDG3, less research has focused on tracking spending towards this goal. We used spending estimates to measure progress in financing the priority areas of SDG3, examine the association between outcomes and financing, and identify where resource gains are most needed to achieve the SDG3 indicators for which data are available