Development of a Single-Axis Sun Seeker using Three Sensors

The output power generated by the solar photovoltaic panel is directly proportional to the amount of solar energy it receives. Therefore, for maximum efficiency, a solar photovoltaic panel must be perpendicular to the sun. As a result of this, a tracking device is required to ensure that solar panels are always directly perpendicular to the direct component of the sun. Such a tracking device is referred to as a sun seeker. This research work describes the development of a single-axis sun seeker using three sensors. Light-dependent resistors are used as sensors. The light intensity received by two of the sensors is compared by two comparators and an appropriate signal is sent to the driving mechanism which moves the solar panel tray until the right and left sensors receive an equal amount of light intensity. The middle sensor was designed to activate the speed control unit of the system when it senses the required light intensity. The whole system runs on a 12V rechargeable battery. A battery charger circuit with automatic cut-off was incorporated to the design to keep the battery topped-up and to prevent overcharging

Future Climate Change Impacts on River Discharge Seasonality for Selected West African River Basins

The changing climate is a concern to sustainable water resources. This study examined climate change impacts on river discharge seasonality in two West African river basins; the Niger river basin and the Hadejia-Jama’are Komadugu-Yobe Basin (HJKYB). The basins have their gauges located within Nigeria and cover the major climatic settings. Here, we set up and validated the hyper resolution global hydrological model PCR-GLOBWB for these rivers. Time series plots as well five performance evaluation metrics such as Kling–Gupta efficiency (KGE),); the ratio of RMSE-observations standard deviation (RSR); per cent bias (PBIAS); the Nash–Sutcliffe Efficiency criteria (NSE); and, the coefficient of determination (r2), were employed to verify the PCR-GLOBWB simulation capability. The validation results showed from satisfactory to very good on individual rivers as specified by PBIAS (−25 to 0.8), NSE (from 0.6 to 0.8), RSR (from 0.62 to 0.4), r2 (from 0.62 to 0.88), and KGE (from 0.69 to 0.88) respectively. The impact assessment was performed by driving the model with climate projections from five global climate models for the representative concentration pathways (RCPs) 4.5 and 8.5. We examined the median and range of expected changes in seasonal discharge in the far future (2070–2099). Our results show that the impacts of climate change cause a reduction in discharge volume at the beginning of the high flow period and an increase in discharge towards the ending of the high flow period relative to the historical period across the selected rivers. In the Niger river basin, at the Lokoja gauge, projected decreases added up to 512 m3/s under RCP 4.5 (June to July) and 3652 m3/s under RCP 8.5 (June to August). The three chosen gauges at the HJKYB also showed similar impacts. At the Gashua gauge, discharge volume increased by 371 m3/s (RCP8.5) and 191 m3/s (RCP4.5) from August to November. At the Bunga gauge, a reduction/increase of -91 m3/s/+84 m3/s (RCP 8.5) and -40 m3/s/+31 m3/s/(RCP 4.5) from June to July/August to October was simulated. While at the Wudil gauge, a reduction/increase in discharge volumes of −39/+133 m3/s (RCP8.5) and −40/133 m3/s (RCP 4.5) from June to August/September to December is projected. This decrease is explained by a delayed start of the rainy season. In all four rivers, projected river discharge seasonality is amplified under the high-end emission scenario (RCP8.5). This finding supports the potential advantages of reduced greenhouse gas emissions for the seasonal river discharge regime. Our study is anticipated to provide useful information to policymakers and river basin development authorities, leading to improved water management schemes within the context of changing climate and increasing need for agricultural expansion

Evaluation of a capacity building intervention on malaria treatment for under-fives in rural health facilities in Niger State, Nigeria.

BACKGROUND: Despite the uptake of parasitological testing into policy and practice, appropriate prescription of anti-malarials and artemisinin-based combination therapy (ACT) in accordance with test results is variable. This study describes a National Malaria Control Programme-led capacity building intervention which was implemented in 10 States of Nigeria. Using the experience of Niger State, this study assessed the effect on malaria diagnosis and prescription practices among febrile under-fives in rural health facilities. METHODS: The multicomponent capacity building intervention consisted of revised case management manuals; cascade training from national to state level carried out at the local government area (LGA) level; and on the job capacity development through supportive supervision. The evaluation was conducted in 28, principally government-owned, health facilities in two rural LGAs of Niger State, one in which the intervention case management of malaria was implemented and the other acted as a comparison area with no implementation of the intervention. Three outcomes were considered in the context of rapid diagnostic testing (RDT) for malaria which were: the prevalence of RDT testing in febrile children; appropriate treatment of RDT-positive children; and appropriate treatment of RDT-negative children. Outcomes were compared post-intervention between intervention and comparison areas using multivariate logistic regression. RESULTS: The intervention did not improve appropriate management of under-fives in intervention facilities above that seen for under-fives in comparison facilities. Appropriate treatment with artemisinin-based combinations of RDT-positive and RDT-negative under-fives was equally high in both areas. However, appropriate treatment of RDT-negative children, when defined as receipt of no ACT or any other anti-malarials, was better in comparison areas. In both areas, a small number of RDT-positives were not given ACT, but prescribed an alternative anti-malarial, including artesunate monotherapy. Among RDT-negatives, no under-fives were prescribed artesunate as monotherapy. CONCLUSION: In a context of significant stock-outs of both ACT medicines and RDTs, under-fives were not more appropriately managed in intervention than comparison areas. The malaria case management intervention implemented through cascade training reached only approximately half of health workers managing febrile under-fives in this setting. Implementation studies on models of cascade training are needed to define what works in what context

Variação sazonal de pressão de pré-consolidação do solo em platação de café de clima tropical

The objective of this study was to describe the seasonal change of precompression stress behavior in coffee plantations in the sub-humid tropic zone of Brazil as affected by agriculture traffic associated with the time since the establishment the coffee plantation, field slope, sampling position in and sampling depths. The coffee plantations on a uniform soil type; Red-Yellow Latosol were aged 2, 7, 18 and 33 years. Areas with side slope of 3, 9 and 15% were selected in these coffee plantations for this study. The soil was sampled at three positions on the coffee plantation row (bottom of traffic line, inter-row and top of traffic line) and at two depths (topsoil and sub-surface). Samples were collected over a one year period for each month of year. The study showed that the time since the establishment of a coffee farm and the slope steepness had significant effect on soil disturbance in mechanized operation. The coffee plantation with longer establishment time and onsteeper terrain had higher precompression stress. The top traffic line presented higher load-bearing capacity than inter-row and bottom traffic line. The sites were more susceptible to compaction in the period from November to January of the year , because the Red-Yellow Latosol presented lower load-bearing capacity than the stress applied by tractor used in coffee management practices.Objetivou-se, neste trabalho, avaliar o comportamento da pressão de pré-consolidação, no decorrer de um ano, em um Latossolo Vermelho-Amarelo cultivado com cafeeiros de diferentes tempos de implantação em diversas declividades do terreno. Este estudo foi conduzido em plantações cafeeiras localizadas em Três Pontas, sul de Minas Gerais. O solo da área de estudo foi classificado como Latossolo Vermelho Amarelo. O trator utilizado na área de estudo foi um Massey Ferguson 265. Esse estudo foi conduzido em plantações cafeeiras com 2, 7, 18 e 33 anos de implantação. Nessas plantações foram selecionadas ruas de café, com 3, 9 e 15% de declividade. Foram coletadas amostras de solo indeformadas e deformadas na linha de tráfego de cima e de baixo e na entrelinha do cafeeiro, nas camadas de 0,0 a 0,03 m e 0,15 a 0,18 m. A avaliação da pressão de pré-consolidação, ao longo de um ano, indicou que o tempo de cultivo e a declividade do terreno tiveram um efeito significativo sobre a alteração estrutural do solo, sendo que as áreas com maior tempo de cultivo e as mais declivosas apresentaram os maiores valores de pressão de pré-consolidação. A linha de tráfego de cima apresentou maior capacidade de suporte de carga do que a entrelinha e a linha de tráfego de baixo. O período de novembro a janeiro foi a época mais crítica para o tráfego agrícola, pois o Latossolo Vermelho-Amarelo apresenta baixa capacidade de suporte de carga e esse é período crítico em termos de umidade no solo

Consequences of restricting antimalarial drugs to rapid diagnostic test-positive febrile children in south-west Nigeria.

OBJECTIVES: To investigate the consequence of restricting antimalarial treatment to febrile children that test positive to a malaria rapid diagnostic test (MRDT) only in an area of intense malaria transmission. METHODS: Febrile children aged 3-59 months were screened with an MRDT at health facilities in south-west Nigeria. MRDT-positive children received artesunate-amodiaquine (ASAQ), while MRDT-negative children were treated based on the clinical diagnosis of non-malaria febrile illness. The primary endpoint was the risk of developing microscopy-positive malaria within 28 days post-treatment. RESULTS: 309 (60.5%) of 511 children were MRDT-positive while 202 (39.5%) were MRDT-negative at enrolment. 18.5% (50/275) of MRDT-positive children and 7.6% (14/184) of MRDT-negative children developed microscopy-positive malaria by day 28 post-treatment (ρ = 0.001). The risk of developing clinical malaria by day 28 post-treatment was higher among the MRDT-positive group than the MRDT-negative group (adjusted OR 2.74; 95% CI, 1.4, 5.4). A higher proportion of children who were MRDT-positive at enrolment were anaemic on day 28 compared with the MRDT-negative group (12.6% vs. 3.1%; ρ = 0.001). Children in the MRDT-negative group made more unscheduled visits because of febrile illness than those in MRDT-positive group (23.2% vs. 12.0%; ρ = 0.001). CONCLUSION: Restricting ACT treatment to MRDT-positive febrile children only did not result in significant adverse outcomes. However, the risk of re-infection within 28 days was significantly higher among MRDT-positive children despite ASAQ treatment. A longer-acting ACT may be needed as the first-line drug of choice for treating uncomplicated malaria in high-transmission settings to prevent frequent re-infections

Serum uric acid and left ventricular hypertrophy in hypertensive patients in Ado-Ekiti

Introduction: systemic hypertension is a foremost risk factor for cardiovascular morbidity and mortality. Its actions are manifested on organs like the brain, heart and kidneys. High serum uric acid (SUA) escalates cardiovascular vulnerability in patients with systemic hypertension. Methods: a cross-sectional study was performed in 271 (178 females, 93 males) patients with systemic hypertension. Two hundred and seventy one healthy age and sex matched non-hypertensive persons obliged as controls. Left ventricular hypertrophy (LVH) was estimated by echocardiography. Blood samples were collected for measuring uric acid levels. Results: mean SUA was significantly higher among the hypertensive patients (371±125μmol/L) than in the controls (269 ± 101.4μmol/L; p < 0.001), and the prevalence of hyperuricemia was 46.9% among the hypertensives and 11.1% among the controls (P < 0.001). Independent predictors of SUA were class of systemic hypertension, left ventricular mass index (LVMI), body mass index (BMI) and age. However, class of hypertension was the best independent predictor of SUA levels in the multivariate regression model (β = 0.597). Linear regression revealed SUA levels ≥ 430μmols/l as a predictor of stage 2 hypertension (F = 26.620, p = < 0.001). Among the hypertensive patients, LVH was present in 39.3% of those with hyperuricemia and in 28.0% of those with normal SUA levels (p = 0.003). Conclusion: results indicate serum uric acid is positively correlated with hypertension and a reliable indicator of LVH in study population

Compactação do solo durante as operações de colheita em cinco solos tropicais de diferentes texturas sob florestas de eucalipto

O tráfego de máquinas durante as operações de colheita e baldeio da madeira tem sido identificado como a principal fonte de degradação da estrutura do solo no sistema de produção florestal. A suscetibilidade à compactação e a compactação causada por cada operação de colheita florestal diferem de acordo com inúmeros fatores (como resistência mecânica do solo, textura, tipo de equipamento, intensidade de tráfego, entre muitos outros), o que demanda a adequada avaliação da compactação do solo sob diferentes condições de tráfego. Os objetivos deste estudo foram determinar a suscetibilidade à compactação de cinco classes de solo com diferentes texturas sob florestas de eucalipto através de seus modelos de capacidade de suporte de carga; e determinar, com o uso destes modelos e da pressão de pré-consolidação obtida após as operações de colheita florestal o efeito da intensidade de tráfego com diferentes maquinários na ocorrência de compactação do solo. Amostras indeformadas foram coletadas antes e após as operações de colheita florestal, sendo então submetidas a ensaios de compressão uniaxial para determinação das pressões de pré-consolidação. Os solos de textura mais grosseira sofreram maior compactação. No LVd2 argiloso, a intensidade de tráfego de até quatro passadas do Forwarder limitou a ocorrência de compactação a um terço das amostras, enquanto no PVd franco-arenoso todas as amostras na camada de 0-3 cm foram compactadas independente da intensidade de tráfego. O Feller Buncher e o Clambunk apresentaram alto potencial de provocar compactação do solo mesmo com apenas uma ou duas passadas. O uso dos modelos de capacidade de suporte de carga e da pressão de pré-consolidação após as operações de colheita e baldeio permitiram melhor compreensão do processo de compactação em solos florestais.Traffic of farm machinery during harvest and logging operations has been identified as the main source of soil structure degradation in forestry activity. Soil susceptibility to compaction and the amount of compaction caused by each forest harvest operation differs according to a number of factors (such as soil strength, soil texture, kind of equipment, traffic intensity, among many others), what requires the adequate assessment of soil compaction under different traffic conditions. The objectives of this study were to determine the susceptibility to compaction of five soil classes with different textures under eucalyptus forests based on their load bearing capacity models; and to determine, from these models and the precompression stresses obtained after harvest operations, the effect of traffic intensity with different equipment in the occurrence of soil compaction. Undisturbed soil samples were collected before and after harvest operations, being then subjected to uniaxial compression tests to determine their precompression stress. The coarse-textured soils were less resistant and endured greater soil compaction. In the clayey LVd2, traffic intensity below four Forwarder passes limited compaction to a third of the samples, whereas in the sandy loam PVd all samples from the 0-3 cm layer were compacted regardless of traffic intensity. The Feller Buncher and the Clambunk presented a high potential to cause soil compaction even with only one or two passes. The use of soil load bearing capacity models and precompression stress determined after harvest and logging operations allowed insight into the soil compaction process in forestry soils