17 research outputs found

    Hydrocarbon Generative Windows Determination Using Geomathematical Model: Case Study from Ogbogede Field, Niger Delta, Nigeria

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    Oil and gas generative windows of source rocks in Niger Delta have been determined by applying a mathematical model to geotemperature data from the wells of Ogbogede oil field. GR and Resistivity log signatures show that the Benin and Agbada Formations comprises massive sands with clay intercalations while the Agbada Formation comprises alternate sequence of sandstones and shales. The geothermal gradients for the field range from 1.4oC/100m to 2oC/100m with an average of 1.8oC/100m and standard deviation of 0.2oC/100m. Geotemperature analysis of shales of the Agbada Formation varies from 58.92oC-107.6oC, indicating that they are thermally mature and within the oil generative window, at depths varying approximately from 1833.30 m to 5166.67m. The gas window occurs from 5166.67 m to 11000 m. This work has provided a mathematical method of source rock evaluation to compliment geochemistry. The outcome is a very important tool, which can be applied to other fields and sedimentary basins in hydrocarbon exploration. Keywords: Hydrocarbon Generative Windows, Geotemperature dat

    Microfossil Assemblages of the Subsurface Parts of the Enugu Formation: Proxies to Depositional Environment and Age of the Formation

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    Two boreholes sunk into Enugu Formation within Enugu Metropolis were logged from the base to the top and samples collected were analyzed for palynomorphs and foraminifera in order to interpret the paleoenvironment and assign age to the formation. Four lithofacies identified include; dark fissile shale lithofacies, heterolithic lithofacies, sand laminated shale lithofacies and greyish shale lithofacies. Palynomorphs recovered consist of pteridophytic spores, angiosperm pollen, fungal spores and Botryoccocus braunii.  Echitriporites trianguliformis, Cythidites sps,. Retitricolporite sp., Retidiporite magdalenensis, Laevigatosporites sp., Zlivisporites blanensis among others were recorded. Five genera of arenaceous benthic foraminifera (Ammobaculites sps., Haplophragmoides sp.,, Trochamina sp., Ammotium sp. and Saccamina sp.) dominated by Ammobaculites sps. were also recovered. The coarsening upwards of the lithofacies succession from basal shale to sand laminated greyish shale lithofacies and the heterolithic lithofacies observed in borehole 1 is an attribute typical of a prograding sea. Evidences from the lithofacies and association, palynomorphs and foraminiferal assemblages showed sediment deposition in a marginal marine setting. Low abundance and diversity of the arenaceous foraminiferal species with the predominance of Ammobaculites sps. is characteristics seen in almost all the samples analyzed. These are suggestive of stressful environment due to low water salinity, rapid sedimentation with influx from terrestrial environment which resulted to stagnant and restricted low oxygen bottom water condition. Keywords: Palynomorphs, Lithofacies, Foraminifera, Environment, Deposition, Shal

    Lithofacies and Pebble Morphogenesis: Keys to Paleoenvironmental Interpretation of the Nkporo Formation, Afikpo Sub-Basin, Nigeria

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    The Nkporo Formation in the Afikpo Subbasin, Nigeria, is dominantly shaly but contains two sandstone members within it. These sandstones host vein quartz pebble beds and dispersed clasts which have been used for pebble morphometric analysis. As independent functions and dependent variables, pebble morphometric indices of Coefficient of Flatness, Elongation Ratio, Maximum Projection Sphericity, Oblate-Prolate Index, Roundness and Form suggest deposition of the sandstones in fluvio-deltaic to littoral settings. Lithofacies analysis identified six lithofacies, grouped into estuarine delta and marine offshore lithofacies associations. These include trough cross-bedded sandstone, ophiomorpha burrowed, wave/rippled and planar cross-bedded lithofacies, Inclined heterolithic lithofacies, fine grained, silty sandstone, lignite/coals, shales/mudstone, interbedded with limestones and oolitic ironstones lithofacies. The estuarine lithofacies association shows a tripartite subdivision into meandering estuarine and tidal point bars overlain by estuary funnel tidal creek sandstones, carbonaceous beds; and estuary mouth tidal and barriers bars and shallow marine shales in a drowned incised valley. The fining upwards lithofacies pattern suggests deepening and transgression of the sea in a tidal estuarine setting. Keywords: Lithofacies, Lithofacies association, Pebble morphogenesis, Paleoenvironments, Tidal estuar

    Tide-generated Sedimentary Structures, Lithofacies and Particle Size Distribution: Proxies to the depositional setting of the Ajali Sandstone in the Anambra Basin, Southeastern Nigeria.

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    Herringbone cross stratification, mud draped foresets, reactivation surfaces, tidal bundles, flaser beddings, ripple and horizontal laminations were identified on the Ajali Sandstone studied. The biogenic structures occur as dominantly vertical to sub-vertical and u -tubed burrows of the Skolithos ichnofacies commonly Skolithos verticalis and Ophiomorpha nodosa. Occasional Thalassinoides and Teichichnus isp burrows of the Cruziana Ichnofacies also occur. Three lithofacies were identified and these include; the medium to coarse grained cross bedded sandstone lithofacies, Fine grained cross bedded sandstone lithofacies and the mudstone lithofacies. The paleocurrent pattern from cross bed azimuths shows a bimodal – bipolar pattern indicative of tidal process. The grain size frequency histograms indicate both unimodal and bimodal asymmetrical patterns with shifting modes. The cumulative frequency curves suggest traction, saltation and suspension as the mechanisms of the sediment transport. The bivariate plots of the discriminant functions (Y1, Y2 and Y3) for the sands suggest deposition in a shallow agitated marine environment. Intertidal to subtidal shallow marine depositional setting is proposed for the Ajali Sandstone. Key word: Tide, Sedimentary structures, Particle size, Lithofacies, Subtidal, Depositional settin

    Tuberculous Enteritis Presenting as Acute Appendicitis and Perirectal Abscess

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    Mycobacterium tuberculosis has a wide variety of presentations. A rare occurrence is gastrointestinal tuberculosis. It may occur anywhere along the alimentary canal but usually occurs in the ileocecum with rare involvement of the appendix

    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

    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 2·5th percentile and 100 as the 97·5th 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

    Emergence and spread of two SARS-CoV-2 variants of interest in Nigeria.

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    Identifying the dissemination patterns and impacts of a virus of economic or health importance during a pandemic is crucial, as it informs the public on policies for containment in order to reduce the spread of the virus. In this study, we integrated genomic and travel data to investigate the emergence and spread of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants of interest in Nigeria and the wider Africa region. By integrating travel data and phylogeographic reconstructions, we find that these two variants that arose during the second wave in Nigeria emerged from within Africa, with the B.1.525 from Nigeria, and then spread to other parts of the world. Data from this study show how regional connectivity of Nigeria drove the spread of these variants of interest to surrounding countries and those connected by air-traffic. Our findings demonstrate the power of genomic analysis when combined with mobility and epidemiological data to identify the drivers of transmission, as bidirectional transmission within and between African nations are grossly underestimated as seen in our import risk index estimates

    Global, regional, and national age-sex-specific mortality and life expectancy, 1950–2017: a systematic analysis for the Global Burden of Disease Study 2017

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    © 2018 The Author(s). Background: Assessments of age-specifc mortality and life expectancy have been done by the UN Population Division, Department of Economics and Social Afairs (UNPOP), the United States Census Bureau, WHO, and as part of previous iterations of the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD). Previous iterations of the GBD used population estimates from UNPOP, which were not derived in a way that was internally consistent with the estimates of the numbers of deaths in the GBD. The present iteration of the GBD, GBD 2017, improves on previous assessments and provides timely estimates of the mortality experience of populations globally. Methods: The GBD uses all available data to produce estimates of mortality rates between 1950 and 2017 for 23 age groups, both sexes, and 918 locations, including 195 countries and territories and subnational locations for 16 countries. Data used include vital registration systems, sample registration systems, household surveys (complete birth histories, summary birth histories, sibling histories), censuses (summary birth histories, household deaths), and Demographic Surveillance Sites. In total, this analysis used 8259 data sources. Estimates of the probability of death between birth and the age of 5 years and between ages 15 and 60 years are generated and then input into a model life table system to produce complete life tables for all locations and years. Fatal discontinuities and mortality due to HIV/AIDS are analysed separately and then incorporated into the estimation. We analyse the relationship between age-specifc mortality and development status using the Socio-demographic Index, a composite measure based on fertility under the age of 25 years, education, and income. There are four main methodological improvements in GBD 2017 compared with GBD 2016: 622 additional data sources have been incorporated; new estimates of population, generated by the GBD study, are used; statistical methods used in diferent components of the analysis have been further standardised and improved; and the analysis has been extended backwards in time by two decades to start in 1950. Findings: Globally, 18·7% (95% uncertainty interval 18·4-19·0) of deaths were registered in 1950 and that proportion has been steadily increasing since, with 58·8% (58·2-59·3) of all deaths being registered in 2015. At the global level, between 1950 and 2017, life expectancy increased from 48·1 years (46·5-49·6) to 70·5 years (70·1-70·8) for men and from 52·9 years (51·7-54·0) to 75·6 years (75·3-75·9) for women. Despite this overall progress, there remains substantial variation in life expectancy at birth in 2017, which ranges from 49·1 years (46·5-51·7) for men in the Central African Republic to 87·6 years (86·9-88·1) among women in Singapore. The greatest progress across age groups was for children younger than 5 years; under-5 mortality dropped from 216·0 deaths (196·3-238·1) per 1000 livebirths in 1950 to 38·9 deaths (35·6-42·83) per 1000 livebirths in 2017, with huge reductions across countries. Nevertheless, there were still 5·4 million (5·2-5·6) deaths among children younger than 5 years in the world in 2017. Progress has been less pronounced and more variable for adults, especially for adult males, who had stagnant or increasing mortality rates in several countries. The gap between male and female life expectancy between 1950 and 2017, while relatively stable at the global level, shows distinctive patterns across super-regions and has consistently been the largest in central Europe, eastern Europe, and central Asia, and smallest in south Asia. Performance was also variable across countries and time in observed mortality rates compared with those expected on the basis of development. Interpretation: This analysis of age-sex-specifc mortality shows that there are remarkably complex patterns in population mortality across countries. The fndings of this study highlight global successes, such as the large decline in under-5 mortality, which refects signifcant local, national, and global commitment and investment over several decades. However, they also bring attention to mortality patterns that are a cause for concern, particularly among adult men and, to a lesser extent, women, whose mortality rates have stagnated in many countries over the time period of this study, and in some cases are increasing

    Lithofacies, Palynology and Facies Association: Keys to Paleogeographical Interpretation of the Enugu and the Mamu Formations of Southeastern Nigeria

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    The lithofacies, palynological assemblages and facies association have been employed in the interpretation of depositional setting, paleogeography and age of the Enugu and the Mamu Formations of the Anambra Basin, southeastern Nigeria. Palynological analysis yielded index sporomorphs and marine dinoflagellates typical of the Late Campanian to Early Maastrichtian for the Enugu Formation and Early- Mid Maastrichtian for the Mamu Formation. The coarsening upwards characteristics of the lithofacies and the general decrease to the absence of marine dinoflagellates coupled with an increase in the abundance of sporomorphs from the Enugu Formation into the Mamu Formation suggest shallowing of the sea.  There is also a gradation from transgressive to regressive facies association. Late Campanian marine transgression deposited the basal part of the Enugu Formation. Seaward advancement of the shoreline commenced during the Early Maastrichtian in the Enugu Formation and continued into the Mid Maastrichtian in the Mamu Formation.   Key words: Paleogeography, Sporomorph, Lithofacies, Dinoflagellate, Transgression, Regressio
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