Prediction of Rainfall Magnitudes and Variations in Nigeria

Rainfall data from 14 locations in Nigeria (six in the north and eight in the south) were collected for the period spanning 1980 to 2002. The data were subjected to analysis using five different methods of hydrologic forecasting namely: Fuller, Gumbel, Powell, Ven Te Chow and stochastic methods. It was found that Fuller’s method overestimated rainfall magnitude in all locations by a large margin. Powell’s method underestimated rainfall magnitude in all locations studied. Ven Te Chow’s method gave the best prediction in all cases except for Enugu in which case Gumbel’s method was found to be more appropriate. Gumbel’s method closely follows Chow’s method in accuracy for all locations. The analyses show that the maximum 1000 years rainfall is 1100mm and will probably occur in around Calabar. Variations in monthly rainfall magnitude were found to be more in the north and less in the south. It is therefore recommended that the Chow’s method and the Gumbel’s method be adopted for rainfall forecasting in Nigeria

Effective Hydraulic Conductivity for a Soil of Variable Pore Size with Depth

Two models were derived for the estimation of effective hydraulic conductivity (Ke) of a soil layer based on exponential and inverse square variation of hydraulic conductivity with soil depth. Darcy’s law was applied to a vertical soil stratum subdivided into a finite number of layers. The relationship between Ke and layer thickness is of quadratic form with R2 ≈ 1.As the layer thickness increases, the values of Ke for the exponential model increases drastically, exceeding the Ke estimate of the power model. The percentage difference between the two models assumes an asymptotic form to the y-axis at a percentage difference of 5%, as the size of layer approaches zero. power model gives lower estimates of Ke than the exponential model within soil depth range of 1.5m ≤ D ≤ 3.2m for n = 2; 0.8m ≤ D ≤ 1.9m for n = 50; and 0.7m ≤ D ≤ 1.9m for n = 100 and above. For very shallow soil stratum (D ≤ 2), the exponential model gives better and more realistic estimates of Ke than the power model; while for medium to deep soil stratum (D ≥ 2), the power model gives better estimates of Ke.http://dx.doi.org/10.4314/njt.v34i3.3

The Effects of Off Take Angle on the Velocity Distribution and Rate of Siltation of Canals

The problem of excessive siltation in canals (navigation, irrigation, water supply, etc) was tackled by the Schwarz-Christoffel transformation, neglecting gravity and assuming a constant depth of flow. This implies that large off take angles will encourage more intake of sediments by the canal. In addition, it was also observed that large off take angles exhibit higher and lower (wider range) velocities. That is, near the stagnation point, a large off take angle will posses lower velocities than small off take angles thus encouraging siltation, while near the point of infinite velocity, a large off take angle will posses higher velocities thereby increasing sediment intake by canal. It is therefore recommended that canals off take angles should be as small as possible but not too small. If the off take angle is too small, the bank between the branch canal and the main canal will be eroded gradually leading to flooding and eventual destruction of the canal. The results obtained can be applied to navigation, irrigation and water supply canals. The results obtained show that the larger the off take angle, the higher will be the off take discharge as well as the off take entrance velocity distribution. The results were found to agree with both laboratory data obtained using a model and field data, giving correlation coefficients of 0.76, 0.77 and 0.62

A Rational Approach to Septic Tank Design

A new approach to the design of septic tanks was developed based on a number of critical parameters, namely: residual detention time, minimum residual detention time, residual depth and minimum residual depth. This method involved rst specifying a desired desludging interval. This interval was then substituted in a septage accumulation model to obtain the volume of sludge accumulated in this time interval. Using a minimum detention time of 24 hours and a desired minimum residual depth, the plan area of the tank was then determined and hence, the depth of sludge volume. The total depth of the tank was obtained as the sum of the sludge depth, residual depth and depth of reserve space. The length and width of the tank were also obtained from the plan area by using a length to width ratio (L/W) ranging between 2 to 4 or any other range depending on land conguration. Design charts and a Microsoft Excel based design programme were produced to aid the design of septic tanks. A predetermined desludging interval ensures septic tanks are effcient and durable

Performance evaluation of clay-sawdust composite filter for point of use water treatment

Water borne diseases have remained a major challenge in most developing countries. This is usually as a result of lack of access to clean water and contamination associated with water fetching and conveyance. This work explores the possibility of improving water quality and eliminating the possibility of recontamination by the use of point of use (POU) water filters made from cheap locally available materials. The performance of POU water filters for the purification of water obtained from various sources was investigated.  Sawdust was used as a burnout material in order to enhance the rate of filtration. The clay was first characterized and then various proportions (5%, 10%, 20%, 30% and 50% by weight) of sawdust were mixed with the clay for filter production. The clay was found to have a specific gravity of 2.4, a high liquid limit of 81.6% and a medium plastic limit of 48.54%. The flow rates of the filters ranged between 0.0005litres/hr for the filter with 5% sawdust and 0.8litres/hr for the filter with 50% sawdust. The average removal of suspended solids (SS) and biochemical oxygen demand (BOD) was 98.6% and 33% respectively while the mean Log10 reduction in total count (TC) was 93.1%. Result of analysis of variance showed that there was no significant difference between the performances of the filters. However, there was a significant difference between the flow rates with F(18.71) > F critical (5.14). This implies that while burnout materials improve water quality, increasing burnout materials in clay filters beyond 50% does not significantly affect the performance for the filter with respect to the quality of effluent but with respect to flow rate. http://dx.doi.org/10.4314/njt.v35i4.3

Ranking of diagnostic features of childhood pulmonary tuberculosis by medical doctors in southeastern Nigeria

Objective: To rank diagnostic features of childhood pulmonary tuberculosis; and to determine the effect of working in tuberculosis Directly Observed Treatment Short Course (DOTS) facilities on the ranking of these features by medical doctors. Methods: A cross sectional descriptive study, using structured questionnaires to collect data from medical doctors whose daily routine included attending to sick children in 34 selected children outpatient clinics and TB DOTS centers in southeastern Nigeria. Results: Approximately, one quarter (25.3% or 56 of 221) of respondents worked in Directly Observed Treatment Short course (DOTS) clinics, while three quarters (74.7% or 165 of 221) worked in nonDOTSclinics. Majority of the respondents (69.7%) ranked chronic persistent cough (1), 42.5 % ranked weight loss and failure to thrive (2), another 27.7% ranked weight loss and failure to thrive (3), while 17.6% and 21.7% ranked History of contact with adult index case and radiographic abnormalities, (4) and (5), respectively. The study found that the percentage of doctors working in DOTS clinics who ranked weight loss and failure to thrive (2) was statistically and significantly higher than those of non-DOTS respondents. Conclusions: The most important symptoms/signs on which medical doctors based their diagnosis of childhood pulmonary tuberculosis include cough, weight loss and failure to thrive, history of contact with adult with smear positive pulmonary tuberculosis, and radiographic abnormalities consistent with active tuberculosis. There was statistically significant difference between the ranking of weight loss and failure to thrive by doctors working in DOTS clinics and their counterparts in non DOTS clinics. This study showed a decline in the percentage of ranking in both DOTS and Non DOTS respondents as they moved from the first to the fifth.KEY WORDS: Childhood pulmonary tuberculosis, Doctors, Ranking, Diagnostic features, Directly observed treatment short course (DOTS)

Circular Economy: Nigeria Perspective

Nigeria is a lower middle-income country and is ranked as the largest economy in Africa with a gross domestic product of 444.92 billion (www.imf.org). The country is located on the western coast of Africa, has an area of 923, 763 km2 and is bounded by Benin Republic in the west, Niger Republic in the north, Cameroun in the east and Gulf of Guinea in the south

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

Mapping inequalities in exclusive breastfeeding in low- and middle-income countries, 2000–2018

Exclusive breastfeeding (EBF)-giving infants only breast-milk for the first 6 months of life-is a component of optimal breastfeeding practices effective in preventing child morbidity and mortality. EBF practices are known to vary by population and comparable subnational estimates of prevalence and progress across low- and middle-income countries (LMICs) are required for planning policy and interventions. Here we present a geospatial analysis of EBF prevalence estimates from 2000 to 2018 across 94 LMICs mapped to policy-relevant administrative units (for example, districts), quantify subnational inequalities and their changes over time, and estimate probabilities of meeting the World Health Organization's Global Nutrition Target (WHO GNT) of ≥70% EBF prevalence by 2030. While six LMICs are projected to meet the WHO GNT of ≥70% EBF prevalence at a national scale, only three are predicted to meet the target in all their district-level units by 2030.This work was primarily supported by grant no. OPP1132415 from the Bill & Melinda Gates Foundation. Co-authors used by the Bill & Melinda Gates Foundation (E.G.P. and R.R.3) provided feedback on initial maps and drafts of this manuscript. L.G.A. has received support from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brasil (CAPES), Código de Financiamento 001 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (grant nos. 404710/2018-2 and 310797/2019-5). O.O.Adetokunboh acknowledges the National Research Foundation, Department of Science and Innovation and South African Centre for Epidemiological Modelling and Analysis. M.Ausloos, A.Pana and C.H. are partially supported by a grant from the Romanian National Authority for Scientific Research and Innovation, CNDS-UEFISCDI, project no. PN-III-P4-ID-PCCF-2016-0084. P.C.B. would like to acknowledge the support of F. Alam and A. Hussain. T.W.B. was supported by the Alexander von Humboldt Foundation through the Alexander von Humboldt Professor award, funded by the German Federal Ministry of Education and Research. K.Deribe is supported by the Wellcome Trust (grant no. 201900/Z/16/Z) as part of his international intermediate fellowship. C.H. and A.Pana are partially supported by a grant of the Romanian National Authority for Scientific Research and Innovation, CNDS-UEFISCDI, project no. PN-III-P2-2.1-SOL-2020-2-0351. B.Hwang is partially supported by China Medical University (CMU109-MF-63), Taichung, Taiwan. M.Khan acknowledges Jatiya Kabi Kazi Nazrul Islam University for their support. A.M.K. acknowledges the other collaborators and the corresponding author. Y.K. was supported by the Research Management Centre, Xiamen University Malaysia (grant no. XMUMRF/2020-C6/ITM/0004). K.Krishan is supported by a DST PURSE grant and UGC Centre of Advanced Study (CAS II) awarded to the Department of Anthropology, Panjab University, Chandigarh, India. M.Kumar would like to acknowledge FIC/NIH K43 TW010716-03. I.L. is a member of the Sistema Nacional de Investigación (SNI), which is supported by the Secretaría Nacional de Ciencia, Tecnología e Innovación (SENACYT), Panamá. M.L. was supported by China Medical University, Taiwan (CMU109-N-22 and CMU109-MF-118). W.M. is currently a programme analyst in Population and Development at the United Nations Population Fund (UNFPA) Country Office in Peru, which does not necessarily endorses this study. D.E.N. acknowledges Cochrane South Africa, South African Medical Research Council. G.C.P. is supported by an NHMRC research fellowship. P.Rathi acknowledges support from Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, India. Ramu Rawat acknowledges the support of the GBD Secretariat for supporting the reviewing and collaboration of this paper. B.R. acknowledges support from Manipal College of Health Professions, Manipal Academy of Higher Education, Manipal. A.Ribeiro was supported by National Funds through FCT, under the programme of ‘Stimulus of Scientific Employment—Individual Support’ within the contract no. info:eu-repo/grantAgreement/FCT/CEEC IND 2018/CEECIND/02386/2018/CP1538/CT0001/PT. S.Sajadi acknowledges colleagues at Global Burden of Diseases and Local Burden of Disease. A.M.S. acknowledges the support from the Egyptian Fulbright Mission Program. F.S. was supported by the Shenzhen Science and Technology Program (grant no. KQTD20190929172835662). A.Sheikh is supported by Health Data Research UK. B.K.S. acknowledges Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal for all the academic support. B.U. acknowledges support from Manipal Academy of Higher Education, Manipal. C.S.W. is supported by the South African Medical Research Council. Y.Z. was supported by Science and Technology Research Project of Hubei Provincial Department of Education (grant no. Q20201104) and Outstanding Young and Middle-aged Technology Innovation Team Project of Hubei Provincial Department of Education (grant no. T2020003). The funders of the study had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. All maps presented in this study are generated by the authors and no permissions are required to publish them

Mapping geographical inequalities in access to drinking water and sanitation facilities in low-income and middle-income countries, 2000-17

Background Universal access to safe drinking water and sanitation facilities is an essential human right, recognised in the Sustainable Development Goals as crucial for preventing disease and improving human wellbeing. Comprehensive, high-resolution estimates are important to inform progress towards achieving this goal. We aimed to produce high-resolution geospatial estimates of access to drinking water and sanitation facilities. Methods We used a Bayesian geostatistical model and data from 600 sources across more than 88 low-income and middle-income countries (LMICs) to estimate access to drinking water and sanitation facilities on continuous continent-wide surfaces from 2000 to 2017, and aggregated results to policy-relevant administrative units. We estimated mutually exclusive and collectively exhaustive subcategories of facilities for drinking water (piped water on or off premises, other improved facilities, unimproved, and surface water) and sanitation facilities (septic or sewer sanitation, other improved, unimproved, and open defecation) with use of ordinal regression. We also estimated the number of diarrhoeal deaths in children younger than 5 years attributed to unsafe facilities and estimated deaths that were averted by increased access to safe facilities in 2017, and analysed geographical inequality in access within LMICs. Findings Across LMICs, access to both piped water and improved water overall increased between 2000 and 2017, with progress varying spatially. For piped water, the safest water facility type, access increased from 40.0% (95% uncertainty interval [UI] 39.4-40.7) to 50.3% (50.0-50.5), but was lowest in sub-Saharan Africa, where access to piped water was mostly concentrated in urban centres. Access to both sewer or septic sanitation and improved sanitation overall also increased across all LMICs during the study period. For sewer or septic sanitation, access was 46.3% (95% UI 46.1-46.5) in 2017, compared with 28.7% (28.5-29.0) in 2000. Although some units improved access to the safest drinking water or sanitation facilities since 2000, a large absolute number of people continued to not have access in several units with high access to such facilities (>80%) in 2017. More than 253 000 people did not have access to sewer or septic sanitation facilities in the city of Harare, Zimbabwe, despite 88.6% (95% UI 87.2-89.7) access overall. Many units were able to transition from the least safe facilities in 2000 to safe facilities by 2017; for units in which populations primarily practised open defecation in 2000, 686 (95% UI 664-711) of the 1830 (1797-1863) units transitioned to the use of improved sanitation. Geographical disparities in access to improved water across units decreased in 76.1% (95% UI 71.6-80.7) of countries from 2000 to 2017, and in 53.9% (50.6-59.6) of countries for access to improved sanitation, but remained evident subnationally in most countries in 2017. Interpretation Our estimates, combined with geospatial trends in diarrhoeal burden, identify where efforts to increase access to safe drinking water and sanitation facilities are most needed. By highlighting areas with successful approaches or in need of targeted interventions, our estimates can enable precision public health to effectively progress towards universal access to safe water and sanitation. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe