40 research outputs found

    Modelling and Prediction of Gully Initiation in the University of Benin Using the Gultem Dynamic Model

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    For a very long period of time there was environmental equilibrium between rainfall and soil erosion in the University of Benin until man's intervention caused a disruption in the equilibrium by the improper termination of the external drainage structures in the University of Benin, Benin City Nigeria. This led to the initiation of gully erosion which has caused the University a lot of environmental damages and if left unchecked, the effect will escalate and become very devastating and disastrous. The study was to evaluate and analyze the gully erosion problem that is developing in the western end of the University of Benin with a view to providing useful information for future planning, land conservation and control. Topographical Survey of the gully site were carried out using Differential Global Positioning System (GPS) Survey for controls and Total Station  instrument for mapping of gully bed, gully walls and bank. This was to acquire morphological data of the gully site and generate geospatial data needed for monitoring the progressive growth of the gully. Using the generated 3D co-ordinates, spot heights, contour and Triangular Irregular Network models were generated in ARC-GIS environment. Soil samples were collected from the gully site for laboratory analysis and tests carried out included Specific gravity test, Particle size analysis, Compaction test and Shear Strength test in order to ascertain the overall contribution of the soils to the erosion problem. The data obtained from the surveys and investigations were inputed into the GULTEM Dynamic Erosion Model, for the evaluation of the rate of gully channel initiation. From the results the area affected by the gully erosion in this site is 11,100 m2.  The geotechnical investigation carried out, revealed that the clay content of the soil in the area is only about 18%. This makes the soil highly susceptible to erosion as soils with less than 30% clay content are easily erodible. It also showed that the soil is finely graded, fairly cohesive and does not compact well. Information from the geospatial data of the gully site, revealed that the University of Benin Gully became steeper between the years 2005 to 2012 and thereafter the slope began to flatten out. The result of the model showed that the computed rate of gully channel initiation increases initially and then began to decrease steadily with the longitudinal distance of the gully for the period under study and also correlates well with the physical observation of the gully at various time interval monitored..  These models were validated using the data on gully morphology and dynamics from University of Benin Gully Erosion site. Keywords: environmental equilibrium, Gully erosion, Network models, GULTEM Dynamic Model

    Stabilization of Lateritic Soil with Rubber Wood Ash and Lime for Road Construction

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    This study involved the investigation of the stabilizing lateritic soil with rubber wood ash (RWA) and lime for road construction. The index and engineering properties of the soil were carried out. Stabilization of the soil was carried out by mixing the soil by weight with 0%, 2%, 4% and 6% RWA mixed with 0.5%, 1%, 1.5% and 2% lime. The soil was classified as A-6 soil group according to AASHTO soil classification system possessing the following characteristics in its natural state; average moisture content of 18.7%, average specific gravity of 2.83 average liquid limit of 34.72%, average plastic limit of 22.02%, average plasticity index of 12.70% and average California Bearing Ratio of 2.47%. Data obtained revealed that the optimum mix ratio for economic and effectiveness was 4% RWA mixed with 1.5% lime which gave a result of 11.34% for soaked sample and 14.30% for the unsoaked sample respectively. Test results also showed that increase in RWA content increased the optimum moisture content but decreased the maximum dry density. The addition of 2% constant RWA with varying lime from 0.5%-2% lime shows that the MDD decreases consistently from 1.89g/cm3 to 1.63g/cm3 with an increase in OMC from 14.00% to 21.50%. The addition of 4% constant RWA with varying lime from 0.5%-1.5% lime reduce the MDD from the initial value of 1.63g/cm3 at 2% RWA to a constant value of 1.62g/cm3 and then increases to 1.68g/cm3 at 2% lime variation when the additives became too much and vice versa for the OMC. The CBR value of the natural soil is 2.47% which shows that the sample is very poor as subgrade material. The addition of RWA only shows a little improvement but the addition of RWA and lime gave a better result

    Effect of Addition of Carpet Waste Fibres on the Unconfined Compressive Strength of Cohesive Soils Samples from Umutu, Agbor and Obiaruku in Delta State, Nigeria

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    With the latest trend in the beautification of most homes and offices, there has been a great shift from the use of carpets to floor tile and as such most of these carpets have become waste and causing environmental pollution. Therefore the objective of this paper was to evaluate the effect of adding carpet waste fibre on unconfined comprehensive strength of cohesive soil samples from Umutu, Agbor and Obiaruku in Delta State, Nigeria using standard techniques. The results showed that the maximum dry  density (MDD) of the natural soil samples from Umutu, Agbor and Obiaruku  were 1.76g/cm3, 1.73 g/cm3 and 1.72 g/cm3 respectively while their respective OMC were 13.6%, 13.86% and 14.2%. The UCS of the natural soil samples were 68.6kN/m2, 73.77kN/m2 and 76.69kN/m2 respectively. The MDD decreased from 1.73 g/cm3 to 1.675g/cm3, 1.72g/cm3 to 1.66g/cm3 and 1.71 g/cm3 to 1.63 g/cm3 when the natural soils from these study areas respectively were compacted with 0.1% to 0.4% fibre content. Also, the OMC from the respective soils-fibre mix increased from 13.8% to 19.0%, 16.0% to 19.6% and 14.9% to 19.2% respectively. The UCS for the respective soil-fibre mix decreased from 60.38kN/m2 to 52.65kN/m2, 66.28kN/m2 to 57.70kN/m2 and72.39kN/m2 to 57.27kN/m2. Hence, the study showed that the addition of fibre to natural soil decreases the strength of the soil

    Urban Flooding Vulnerability Analysis Using Weighted Linear Method With Geospatial Information System

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    This study was carried out to investigate the causative factors responsible for flooding in Etsako east, Nigeria. The study applied weighted linear method and geospatial information technology to obtain relevant data which were subjected to analysis. Sentinel 2 imagery of the area was downloaded from the United States Geological Survey (USGS) website and analyzed to produced digital elevation model, rainfall distribution, soil texture classification, topographic wetness index (TWI), hillside slope, land use/cover contour and slope maps of the area. Saaty weighted scale (1 – 5) was used to assign importance to the factors selected. The results presented using relevant maps revealed that, TWI (14%), precipitation (14%), distance to river (12%), elevation (11%) and slope (10%) are the major factors responsible for flooding in the area. Using built up areas only (46.57 km2 ); 38.6% of it is within the risk range of High to very High flood vulnerability, moderate vulnerability zone (17.97 km2 ) occupied 27.28%. Low vulnerability zone occupied 22.05%,(10.27 km2 ) while no vulnerability zone occupied 12.05% (5.61 km2). Communities in the high flood vulnerable region includes Iddo, Iyukwe, Iyogeh, Imiegb and Opepwe; flood control measures and early warning systems should be developed to mitigate the impact of flooding in the area

    The Particle Size Distribution of Laterite Soil at Ekosodin, Benin City, Nigeria

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    The laterite soil particle-size distribution provides a preliminary knowledge of the rate of failure and the strength of soil to resist load pressure and subsequent susceptibility to gully erosion. This study was carried out to determine the particle size distribution of laterite soil at Ekosodin, Benin City, Nigeria using appropriate standard methods. This was achieved by collecting a total of twenty soil samples from the gully zone of Ekosodin and carrying out sieve and hydrometer analyses on the recovered soil. The average percentage weight of fines smaller than the following grain diameters: 1.18mm, 0.425mm, 0.075mm, 0.040mm, 0.010mm, 0.003mm, and 0.001mm, were approximately 96%, 74%, 45%, 35%, 28%, 21%, and 15% respectively. The coefficient of uniformity and coefficient of curvature classified the laterite soil as a well graded soil consisting of a representative of all grain sizes in a good complementary proportion. However, the significant quantity of fine in the soil composition made it susceptible to gully erosion in the presence of intense water movement

    Diabetes mortality and trends before 25 years of age: an analysis of the Global Burden of Disease Study 2019

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    Background Diabetes, particularly type 1 diabetes, at younger ages can be a largely preventable cause of death with the correct health care and services. We aimed to evaluate diabetes mortality and trends at ages younger than 25 years globally using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019. Methods We used estimates of GBD 2019 to calculate international diabetes mortality at ages younger than 25 years in 1990 and 2019. Data sources for causes of death were obtained from vital registration systems, verbal autopsies, and other surveillance systems for 1990–2019. We estimated death rates for each location using the GBD Cause of Death Ensemble model. We analysed the association of age-standardised death rates per 100 000 population with the Socio-demographic Index (SDI) and a measure of universal health coverage (UHC) and described the variability within SDI quintiles. We present estimates with their 95% uncertainty intervals. Findings In 2019, 16 300 (95% uncertainty interval 14 200 to 18 900) global deaths due to diabetes (type 1 and 2 combined) occurred in people younger than 25 years and 73·7% (68·3 to 77·4) were classified as due to type 1 diabetes. The age-standardised death rate was 0·50 (0·44 to 0·58) per 100 000 population, and 15 900 (97·5%) of these deaths occurred in low to high-middle SDI countries. The rate was 0·13 (0·12 to 0·14) per 100 000 population in the high SDI quintile, 0·60 (0·51 to 0·70) per 100 000 population in the low-middle SDI quintile, and 0·71 (0·60 to 0·86) per 100 000 population in the low SDI quintile. Within SDI quintiles, we observed large variability in rates across countries, in part explained by the extent of UHC (r2=0·62). From 1990 to 2019, age-standardised death rates decreased globally by 17·0% (−28·4 to −2·9) for all diabetes, and by 21·0% (–33·0 to −5·9) when considering only type 1 diabetes. However, the low SDI quintile had the lowest decline for both all diabetes (−13·6% [–28·4 to 3·4]) and for type 1 diabetes (−13·6% [–29·3 to 8·9]). Interpretation Decreasing diabetes mortality at ages younger than 25 years remains an important challenge, especially in low and low-middle SDI countries. Inadequate diagnosis and treatment of diabetes is likely to be major contributor to these early deaths, highlighting the urgent need to provide better access to insulin and basic diabetes education and care. This mortality metric, derived from readily available and frequently updated GBD data, can help to monitor preventable diabetes-related deaths over time globally, aligned with the UN's Sustainable Development Targets, and serve as an indicator of the adequacy of basic diabetes care for type 1 and type 2 diabetes across nations.publishedVersio

    AI is a viable alternative to high throughput screening: a 318-target study

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    : High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

    Population and fertility by age and sex for 195 countries and territories, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

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    Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10–54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10–14 years and 50–54 years was estimated from data on fertility in women aged 15–19 years and 45–49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49·4% (95% uncertainty interval [UI] 46·4–52·0). The TFR decreased from 4·7 livebirths (4·5–4·9) to 2·4 livebirths (2·2–2·5), and the ASFR of mothers aged 10–19 years decreased from 37 livebirths (34–40) to 22 livebirths (19–24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83·8 million people per year since 1985. The global population increased by 197·2% (193·3–200·8) since 1950, from 2·6 billion (2·5–2·6) to 7·6 billion (7·4–7·9) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2·0%; this rate then remained nearly constant until 1970 and then decreased to 1·1% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2·5% in 1963 to 0·7% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2·7%. The global average age increased from 26·6 years in 1950 to 32·1 years in 2017, and the proportion of the population that is of working age (age 15–64 years) increased from 59·9% to 65·3%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1·0 livebirths (95% UI 0·9–1·2) in Cyprus to a high of 7·1 livebirths (6·8–7·4) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0·08 livebirths (0·07–0·09) in South Korea to 2·4 livebirths (2·2–2·6) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0·3 livebirths (0·3–0·4) in Puerto Rico to a high of 3·1 livebirths (3·0–3·2) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2·0% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress

    Measuring progress from 1990 to 2017 and projecting attainment to 2030 of the health-related Sustainable Development Goals for 195 countries and territories: a systematic analysis for the Global Burden of Disease Study 2017

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    Background: Efforts to establish the 2015 baseline and monitor early implementation of the UN Sustainable Development Goals (SDGs) highlight both great potential for and threats to improving health by 2030. To fully deliver on the SDG aim of “leaving no one behind”, it is increasingly important to examine the health-related SDGs beyond national-level estimates. As part of the Global Burden of Diseases, Injuries, and Risk Factors Study 2017 (GBD 2017), we measured progress on 41 of 52 health-related SDG indicators and estimated the health-related SDG index for 195 countries and territories for the period 1990–2017, projected indicators to 2030, and analysed global attainment. Methods: We measured progress on 41 health-related SDG indicators from 1990 to 2017, an increase of four indicators since GBD 2016 (new indicators were health worker density, sexual violence by non-intimate partners, population census status, and prevalence of physical and sexual violence [reported separately]). We also improved the measurement of several previously reported indicators. We constructed national-level estimates and, for a subset of health-related SDGs, examined indicator-level differences by sex and Socio-demographic Index (SDI) quintile. We also did subnational assessments of performance for selected countries. To construct the health-related SDG index, we transformed the value for each indicator on a scale of 0–100, with 0 as the 2\ub75th percentile and 100 as the 97\ub75th percentile of 1000 draws calculated from 1990 to 2030, and took the geometric mean of the scaled indicators by target. To generate projections through 2030, we used a forecasting framework that drew estimates from the broader GBD study and used weighted averages of indicator-specific and country-specific annualised rates of change from 1990 to 2017 to inform future estimates. We assessed attainment of indicators with defined targets in two ways: first, using mean values projected for 2030, and then using the probability of attainment in 2030 calculated from 1000 draws. We also did a global attainment analysis of the feasibility of attaining SDG targets on the basis of past trends. Using 2015 global averages of indicators with defined SDG targets, we calculated the global annualised rates of change required from 2015 to 2030 to meet these targets, and then identified in what percentiles the required global annualised rates of change fell in the distribution of country-level rates of change from 1990 to 2015. We took the mean of these global percentile values across indicators and applied the past rate of change at this mean global percentile to all health-related SDG indicators, irrespective of target definition, to estimate the equivalent 2030 global average value and percentage change from 2015 to 2030 for each indicator. Findings: The global median health-related SDG index in 2017 was 59\ub74 (IQR 35\ub74–67\ub73), ranging from a low of 11\ub76 (95% uncertainty interval 9\ub76–14\ub70) to a high of 84\ub79 (83\ub71–86\ub77). SDG index values in countries assessed at the subnational level varied substantially, particularly in China and India, although scores in Japan and the UK were more homogeneous. Indicators also varied by SDI quintile and sex, with males having worse outcomes than females for non-communicable disease (NCD) mortality, alcohol use, and smoking, among others. Most countries were projected to have a higher health-related SDG index in 2030 than in 2017, while country-level probabilities of attainment by 2030 varied widely by indicator. Under-5 mortality, neonatal mortality, maternal mortality ratio, and malaria indicators had the most countries with at least 95% probability of target attainment. Other indicators, including NCD mortality and suicide mortality, had no countries projected to meet corresponding SDG targets on the basis of projected mean values for 2030 but showed some probability of attainment by 2030. For some indicators, including child malnutrition, several infectious diseases, and most violence measures, the annualised rates of change required to meet SDG targets far exceeded the pace of progress achieved by any country in the recent past. We found that applying the mean global annualised rate of change to indicators without defined targets would equate to about 19% and 22% reductions in global smoking and alcohol consumption, respectively; a 47% decline in adolescent birth rates; and a more than 85% increase in health worker density per 1000 population by 2030. Interpretation: The GBD study offers a unique, robust platform for monitoring the health-related SDGs across demographic and geographic dimensions. Our findings underscore the importance of increased collection and analysis of disaggregated data and highlight where more deliberate design or targeting of interventions could accelerate progress in attaining the SDGs. Current projections show that many health-related SDG indicators, NCDs, NCD-related risks, and violence-related indicators will require a concerted shift away from what might have driven past gains—curative interventions in the case of NCDs—towards multisectoral, prevention-oriented policy action and investments to achieve SDG aims. Notably, several targets, if they are to be met by 2030, demand a pace of progress that no country has achieved in the recent past. The future is fundamentally uncertain, and no model can fully predict what breakthroughs or events might alter the course of the SDGs. What is clear is that our actions—or inaction—today will ultimately dictate how close the world, collectively, can get to leaving no one behind by 2030
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