17 research outputs found
Effects of Compact Fluorescence Light (Cfl) Bulbs on Power Quality
In recent time, the power quality has attracted a lot of attention due to extensive emphasis by power utility on the power system efficiency and end users awareness of power quality issues. This has occurred mainly due to the sensitivity of the modern equipment and the deregulation of the power distribution. In addition, there are usually massive losses both to power utility and end users due to poor power quality supplies which fall below the set standards. Power quality primarily consists of voltage dip/ swell, power system interruptions, harmonic distortions, voltage flickers and frequency deviations. This study looks at effect of CFL bulbs on power system in relation to harmonic distortions and low power factor inherently associated by CFL. It has established that the bulbs generate substantial harmonic distortions and leading power factor. Combination of incandescent and CFL bulbs in one circuit was noted to improves the power quality. Keywords: CFL bulb, Harmonic distortion, Power factor, Reactive powe
Improving Power Distribution Efficiency On Power Lines
This paper discusses the power factor of transmission and distribution lines for selected power utility substations. The choice of selection of lines was based on the nature of the load and the status of the loading. The data collected and analyzed revealed that some feeder lines at most of substations are distributing active power at low PF below the grid threshold limit. Feeder lines mainly supplying domestic loads have their PF generally low and on the other hand, it was found that feeder lines supplying industrial loads have power factor well above the statutory limit. It is concluded that it is imperative to compensate the reactive current on feeder lines supplying mainly domestic loads in the vicinity of the loads i.e. near the distribution transformers to improve the power factor of these feeder lines in order to increase distribution efficiency and improve the voltage profile. Keywords: Reactive power, VAr compensator, Power factor, Energy meter, Feeder line
Impact of cropping systems on soil properties, nutrient availability and their carbon sequestration potential in Shiwalik hills of Himachal Pradesh
The impact of cropping systems on soil properties, nutrient availability and their carbon sequestration potential was studied during the years 2014 and 2015 in Shiwalik hills of Himachal Pradesh. The four commonly occurring cropping systems namely vegetable, fruit, cereal crop and agroforestry were selected. Uncultivated land in the region was considered as control. In total, there were five treatments which were replicated six times under randomized block design. The study indicated that the cropping systems in the Shiwalik hills varied significantly (P=0.05) with respect to their impact on soil properties, nutrient availability and carbon sequestration potential. The pH and EC was in the range of 6.04 to 6.90 and 0.094 to 0.138 dSm-1, respectively and were normal in range. Organic carbon and bulk density in surface soils ranged from 8.06 to 9.70 g kg-1 and 1.19 to 1.34 Mg m-3, respectively. The available NPK was highest (267.21, 19.99, 172.42 kg ha-1) under vegetable based cropping system as compared to other systems. Carbon density in surface soil ranged from 11.33 to 15.39 Mg C ha-1 and total carbon sequestered upto 30cm soil depth ranged from 601.96 to 12646.29 Gg. The study indicated that in Shiwalik hills of Himachal Pradesh, the commonly occurring cropping systems did not influence the soil properties and nutrient availability adversely. Agroforestry based cropping system is having highest potential of sequestering soil carbon in Shiwalik hills. Therefore to adapt to changing climatic situation and to mitigate its effect in the region, agroforestry based cropping system need to be encouraged
Access to Educational Opportunities for Latino Students in Four Massachusetts School Districts
This report was prompted by the pressing concerns over the high failure rates of Latino students on the Massachusetts Comprehensive Assessment System (MCAS) exam. While 27% of White students failed the English portion of the MCAS test and 38% failed the Mathematics portion in 2000, the corresponding rates for Latino students were 66% and 79% respectively (Massachusetts Department of Education, 2000a). There is a great urgency to understand why Latino students score substantially behind students from other racial/ethnic groups. This urgency stems from the reality that students currently enrolled in the 10th grade will be required to pass this exam in order to receive a high school diploma in 2003
Rainfall and Temperature Trends and Variability in Arid and Semi-arid Lands of Kitui County, Kenya
A study was carried out to analyse rainfall and temperature trends and variability in selected agro-ecological zones in Kitui County. Climate Hazards Group Infrared Precipitation with Stations (CHIRPS) rainfall dataset was used while temperature data was obtained from the Climatic Research Unit gridded Time Series (CRU TS) dataset. The results indicated that there was a non-significant decreasing trend (p<0.05) in average annual rainfall in all the four agro-ecological zones (p<0.05) for a 30-years period (1988-2018) in the study area. A decreasing trend in March-April-May (MAM) seasonal rainfall trend was reported in the arid and semi-arid agro-ecological zones while an increasing trend was recorded in the transitional and semi-humid zones. For the October-November-December (OND) seasonal rainfall, a non-significant decreasing trend was reported in all the four agro-ecological zones. Additionally, a higher annual rainfall variability was recorded in the drier (arid) and wetter (semi-humid) zones compared to that in semi-arid and transitional zones. Moreover, the study established that there was a spatial variation in both MAM and OND seasonal rainfall variability and that rainfall variability was higher in the OND seasonal rainfall than that of the MAM seasonal rainfall in all the agro-ecological zones. With reference to temperature trends, a statistically significant increasing trend in annual and OND seasonal average maximum and minimum temperatures was reported in all the four agro-ecological zones. Further, the study noted a non-significant increasing trend in maximum and minimum temperatures for the MAM season in all the agro-ecological zones. In regard to temperature variability, the study deduced that there was low temperature variability compared to rainfall variability in all the four agro-ecological zones. The study recommends that location-specific rainfall and temperature analysis should guide planning and implementation of adaptation strategies for effective response to climate variability. Keywords: Agro-ecological Zones, Mann-Kendall Test, Coefficient of Variation, CHIRPS, CRU TS DOI: 10.7176/JEES/12-12-05 Publication date: December 31st 202
Fertilizer Use Issues for Smallholder Agriculture in Tropical Africa
Fertilizer is an essential input for wide-scale sustainable intensification of crop productivity in tropical Africa, but its use by smallholders is often financially constrained. Four fertilizer use issues are addressed. Smallholders need high net returns from their investments, with acceptable risk, which can be achieved with good crop-nutrient-rate choices made in consideration of the farmer’s financial and agronomic context. Soil acidification, which is affected by crop N supply, is best managed with the use of slightly more acidifying but less costly common N fertilizer, e.g., urea, coupled with lime use compared with the use of more costly but less acidifying N fertilizer such as calcium ammonium nitrate. This chapter addresses the feasibility of tailored fertilizer blends for maximizing farmer profit with respect to the nutrient supply cost, the need for flexibility in nutrient application according to the farmer’s context, and the weak justification for tailoring blends based on soil test results. The use of a well-formulated blends is justified in some cases, e.g., for some crops in Rwanda, but the supply of blends does not justify restricting the supply of common fertilizers. Farmers need to be aware that unregulated nontraditional products very often fail to provide the claimed benefits. Fertilizer use, sometimes with timely lime application, can be highly profitable with modest risk with good crop-nutrient-rate choices, adequate free-market fertilizer supply, and avoiding products with unsubstantiated claims
Voluntary Medical Male Circumcision: Translating Research into the Rapid Expansion of Services in Kenya, 2008–2011
Zebedee Mwandi and colleagues discuss Kenya's scale-up of voluntary medical male circumcision services, highlighting government leadership, a clear implementation strategy, and program flexibility and innovation as keys to Kenya's success
Plasmodium-specific atypical memory B cells are short-lived activated B cells
A subset of atypical memory B cells accumulates in malaria and several infections, autoimmune disorders and aging in both humans and mice. It has been suggested these cells are exhausted long-lived memory B cells, and their accumulation may contribute to poor acquisition of long-lasting immunity to certain chronic infections, such as malaria and HIV. Here, we generated an immunoglobulin heavy chain knock-in mouse with a BCR that recognizes MSP1 of the rodent malaria parasite, Plasmodium chabaudi. In combination with a mosquito-initiated P. chabaudi infection, we show that Plasmodium-specific atypical memory B cells are short-lived and disappear upon natural resolution of chronic infection. These cells show features of activation, proliferation, DNA replication, and plasmablasts. Our data demonstrate that Plasmodium-specific atypical memory B cells are not a subset of long-lived memory B cells, but rather short-lived activated cells, and part of a physiologic ongoing B-cell response
Antigen-Specific B Memory Cell Responses to Plasmodium falciparum Malaria Antigens and Schistosoma haematobium Antigens in Co-Infected Malian Children
Polyparasitism is common in the developing world. We have previously demonstrated that schistosomiasis-positive (SP) Malian children have age-dependent protection from malaria compared to matched schistosomiasis-negative (SN) children. Evidence of durable immunologic memory to malaria antigens is conflicting, particularly in young children and the effect of concomitant schistomiasis upon acquisition of memory is unknown. We examined antigen-specific B memory cell (MBC) frequencies (expressed as percentage of total number of IgG-secreting cells) in 84 Malian children aged 4–14 to malaria blood-stage antigens, apical membrane antigen 1 (AMA-1) and merozoite surface protein 1 (MSP-1) and to schistosomal antigens, Soluble Worm Antigenic Preparation (SWAP) and Schistosoma Egg Antigen (SEA), at a time point during the malaria transmission season and a follow-up dry season visit. We demonstrate, for the first time, MBC responses to S. haematobium antigens in Malian children with urinary egg excretion and provide evidence of seasonal acquisition of immunologic memory, age-associated differences in MBC acquisition, and correlation with circulating S. haematobium antibody. Moreover, the presence of a parasitic co-infection resulted in older children, aged 9–14 years, with underlying S. haematobium infection having significantly more MBC response to malaria antigens (AMA1 and MSP1) than their age-matched SN counterparts. We conclude that detectable MBC response can be measured against both malaria and schistosomal antigens and that the presence of S. haematobium may be associated with enhanced MBC induction in an age-specific manner
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030