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

    Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017 : a systematic analysis for the Global Burden of Disease Study 2017

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    Background Global development goals increasingly rely on country-specific estimates for benchmarking a nation's progress. To meet this need, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2016 estimated global, regional, national, and, for selected locations, subnational cause-specific mortality beginning in the year 1980. Here we report an update to that study, making use of newly available data and improved methods. GBD 2017 provides a comprehensive assessment of cause-specific mortality for 282 causes in 195 countries and territories from 1980 to 2017. Methods The causes of death database is composed of vital registration (VR), verbal autopsy (VA), registry, survey, police, and surveillance data. GBD 2017 added ten VA studies, 127 country-years of VR data, 502 cancer-registry country-years, and an additional surveillance country-year. Expansions of the GBD cause of death hierarchy resulted in 18 additional causes estimated for GBD 2017. Newly available data led to subnational estimates for five additional countries Ethiopia, Iran, New Zealand, Norway, and Russia. Deaths assigned International Classification of Diseases (ICD) codes for non-specific, implausible, or intermediate causes of death were reassigned to underlying causes by redistribution algorithms that were incorporated into uncertainty estimation. We used statistical modelling tools developed for GBD, including the Cause of Death Ensemble model (CODErn), to generate cause fractions and cause specific death rates for each location, year, age, and sex. Instead of using UN estimates as in previous versions, GBD 2017 independently estimated population size and fertility rate for all locations. Years of life lost (YLLs) were then calculated as the sum of each death multiplied by the standard life expectancy at each age. All rates reported here are age-standardised. Findings At the broadest grouping of causes of death (Level 1), non-communicable diseases (NC Ds) comprised the greatest fraction of deaths, contributing to 73.4% (95% uncertainty interval [UI] 72.5-74.1) of total deaths in 2017, while communicable, maternal, neonatal, and nutritional (CMNN) causes accounted for 186% (17.9-19.6), and injuries 8.0% (7.7-8.2). Total numbers of deaths from NCD causes increased from 2007 to 2017 by 22.7% (21.5-23.9), representing an additional 7.61 million (7. 20-8.01) deaths estimated in 2017 versus 2007. The death rate from NCDs decreased globally by 7.9% (7.08.8). The number of deaths for CMNN causes decreased by 222% (20.0-24.0) and the death rate by 31.8% (30.1-33.3). Total deaths from injuries increased by 2.3% (0-5-4-0) between 2007 and 2017, and the death rate from injuries decreased by 13.7% (12.2-15.1) to 57.9 deaths (55.9-59.2) per 100 000 in 2017. Deaths from substance use disorders also increased, rising from 284 000 deaths (268 000-289 000) globally in 2007 to 352 000 (334 000-363 000) in 2017. Between 2007 and 2017, total deaths from conflict and terrorism increased by 118.0% (88.8-148.6). A greater reduction in total deaths and death rates was observed for some CMNN causes among children younger than 5 years than for older adults, such as a 36.4% (32.2-40.6) reduction in deaths from lower respiratory infections for children younger than 5 years compared with a 33.6% (31.2-36.1) increase in adults older than 70 years. Globally, the number of deaths was greater for men than for women at most ages in 2017, except at ages older than 85 years. Trends in global YLLs reflect an epidemiological transition, with decreases in total YLLs from enteric infections, respirator}, infections and tuberculosis, and maternal and neonatal disorders between 1990 and 2017; these were generally greater in magnitude at the lowest levels of the Socio-demographic Index (SDI). At the same time, there were large increases in YLLs from neoplasms and cardiovascular diseases. YLL rates decreased across the five leading Level 2 causes in all SDI quintiles. The leading causes of YLLs in 1990 neonatal disorders, lower respiratory infections, and diarrhoeal diseases were ranked second, fourth, and fifth, in 2017. Meanwhile, estimated YLLs increased for ischaemic heart disease (ranked first in 2017) and stroke (ranked third), even though YLL rates decreased. Population growth contributed to increased total deaths across the 20 leading Level 2 causes of mortality between 2007 and 2017. Decreases in the cause-specific mortality rate reduced the effect of population growth for all but three causes: substance use disorders, neurological disorders, and skin and subcutaneous diseases. Interpretation Improvements in global health have been unevenly distributed among populations. Deaths due to injuries, substance use disorders, armed conflict and terrorism, neoplasms, and cardiovascular disease are expanding threats to global health. For causes of death such as lower respiratory and enteric infections, more rapid progress occurred for children than for the oldest adults, and there is continuing disparity in mortality rates by sex across age groups. Reductions in the death rate of some common diseases are themselves slowing or have ceased, primarily for NCDs, and the death rate for selected causes has increased in the past decade. Copyright (C) 2018 The Author(s). Published by Elsevier Ltd.Peer reviewe

    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

    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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