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Geochemical significance of tricyclic and tetracyclic terpanes in source rock extracts from the Offshore Niger Delta Basin,nigeria

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Acta Geochimica 2021年第2期40卷 184-198页

作者： Abiodun B.Ogbesejana Oluwasesan M.Bello Tijjani Ali Uduma A.Uduma Kamaluddeen S.Kabo Oluwadurotimi O.Akintade Department of Applied Chemistry Federal University Dutsin-MaP.M.B.5001Dutsin-MaKatsina StateNigeria Department of Chemical Sciences Koladaisi UniversityIbadanOyo StateNigeria

Tricyclic and tetracyclic terpanes are important constituents of crude oil and source rock ***,they have not been reported in the Offshore Niger Delta Basin,***,the present study investigated the geochemical significance of tricyclic and tetracyclic terpanes in source rock extracts from the Offshore Niger Delta Bain,nigeria with gas chromatography-mass spectrometry(GC-MS).The total relative abundances of tricyclic terpanes,C_(19)TT-C_(21)TT,and C_(23) TT in the rock samples ranged from 82.50 to 96.37%,50.08 to 74.17%,and 25.83 to 49.92%,*** values showed the source rocks were formed from a mixed origin(terrestrial and marine).Among the tricyclic and tetracyclic terpanes identified in the rock extracts,the conventional(C_(20)TT,C_(23)TT,C_(24)TT,C_(24)TeT)and recent(Y1,X1,Z1)were more prominent than all others,indicating mixed input of terrigenous and marine organic *** C_(24)TT/C_(23)TT,C_(24)TeT/(C_(24)TeT+C_(26)TT),C_(19)TT/C_(23)TT,C_(20)TT/C_(23)TT,C_(25)TT/C_(24)TeT,C_(25)TT/C_(26)TT,C_(19)TT/C_(20)TT,C_(24)TeT/C_(26)TT,Z1/(Z1+C_(24)TT),and Y1/(Y1+C_(24)TT)in the rock samples range from 0.33 to 1.30,0.76 to 0.90,0.18 to 0.73,0.34 to 1.05,0.33 to 1.74,0.30 to 1.39,0.31 to0.89,1.66 to 4.33,0.36 to 0.83,and 0.34 to 0.79,*** values further showed that the rock samples were formed from mixed input of terrigenous and marine organic matter and deposited under oxic to suboxic conditions in lacustrine-fluvial/deltaic ***,the C_(24)TeT/C_(20)-26TT,C_(24)TeT/C_(30)HOP,and C_(23)TT/C_(30)HOP ranged from 0.16 to 0.45,0.02 to 0.42,and 0.01 to 0.48,*** range of values suggests that source rocks were within immature to early mature ***,this study showed that tricyclic and tetracyclic terpanes were effective in determining the origin,depositional environments,and thermal maturity of source rocks in the Niger Delta Basin,nigeria.

关键词： Tricyclic terpanes Tetracyclic terpanes Source rocks Niger delta Gas chromatography-mass spectrometry(GC-MS)

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A techno-economic analysis of aquaculture business in Ogun State,nigeria

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Chinese Journal of Oceanology and Limnology 2009年第2期27卷 415-420页

作者： R. O. KAREEM S. B. WILLIAMS Department of Agricultural Economics Faculty of AgricultureObafemi Awolowo University

Fish supplies 25% of the total protein source in developing countries. A techno-economic analysis was performed for developing a good business proposal for aquaculture loans to enhance aquaculture development in nigeria. A case study of catfish Clarias gariepinus framing was conducted in Abeokuta North Local Government of Ogun State, nigeria. The results show that the fixed cost is N18 338 per year, and the variable cost is N459 700 per year, accounting for the largest amount of the total; therefore, a profit of N43 289 per month can be made. Sensitivity analysis was performed to assess any risk(s) that associated with unfavorable changes in government policy with particular reference to monetary policy. Positive net present value shows that the investment in fish farm is economically feasible and the net investment ratio is 3.52. Also, the benefit-cost ratio is 2.17. The internal rate of return (IRR) is 21% showing that the enterprise is able to offset the interest being charged on the loan. It is therefore worthwhile to invest into fish farm business in the study area. The study suggests that to better sustain the local aquaculture business, the government should create a good conducive environment to foster development of the fish farming. Government intervention is urgently needed to solve problems such as in traditional land tenure, grant credit facilities and subsidies, to enhance the aquacultural development in the country.

关键词： aquaculture net present value B-C ratio net-investment-ratio internal rate of return

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A Mother-to-Child Transmission Study in nigeria:The Impact of Maternal HIV Infection and HAART on Plasma Immunoglobulins,Cytokine Profiles and Infant Outcome

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Virologica Sinica 2020年第4期35卷 468-477页

作者： Chinwe O.Ewenighi-Amankwah Charles Chinedum Onyenekwe Ogochukwu Udemba Patience Muogbo Lijun Rong Department of Medical Laboratory Science Ebonyi State UniversityAbakaliki 480214Nigeria Department of Microbiology and Immunology College of MedicineUniversity of Illinois at ChicagoChicagoIL 60612USA Department of Medical Laboratory Science Faculty of Health Science and TechnologyNnamdi Azikiwe UniversityAwka 5025Nigeria Laboratory Unit Mother of Christ Specialist HospitalOguiEnugu 400252Nigeria Monitoring and Evaluation Unit ART DepartmentMother of Christ Specialist HospitalOguiEnugu 400252Nigeria

Prevention of mother-to-child transmission(PMTCT)of HIV with highly active antiretroviral therapy(HARRT)allows the HIV^+pregnant mothers to have vaginal delivery and *** we investigated the maternal plasma immunoglobulin,cytokine secretion and the outcome of the exposed infants among the HIV^+HAART treated pregnan women in *** this study,different plasma immunoglobulins and cytokines were measured in the HIV^+HAART treated pregnant *** culture supernatants of B and T lymphocytes showed lower levels of IFN-γ,IL-10 and *** were lower IFN-γand IL-10 secretions at 1st trimester;however,IL-10 continued to be lower throughout 2nd and 3rd ***-αsecretion significantly decreased as pregnancy progressed to *** were high plasma IgG and low IgM in the HIV^+HAART treated pregnant *** IgG was high during 1st and 3rd *** one year of follow up,all the exposed children were seronegative for HIV-1 and *** delivery and breastfeeding among HIV^+HAART treated mothers have shown to be *** use of HAART by the infected mothers and the use of septrin and niverapin by the exposed infants prevented mother to-child transmission of HIV.

关键词： Human immunodeficiency virus(HIV) Prevention from mother-to-child transmission(PMTCT) Highly active antiretroviral therapy(HAART) Lymphocyte stimulation Mitogen Cytokine Immunoglobulins

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Upper arm composition and nutritional status of school children and adolescents in Abeokuta,Southwest nigeria

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World Journal of Pediatrics 2014年第4期10卷 336-342页

作者： Idowu Odunayo Senbanjo Kazeem Adeola Oshikoya Olisamedua Fidelis Njokanma Department of Pediatrics and Child Health Lagos State University College of MedicinePMB 21266IkejaLagos State 100001Nigeria Pharmacology Department Lagos State University College of MedicinePMB 21266IkejaLagosNigeria Academic Division of Child Health Medical SchoolUniversity of NottinghamDerbyshire Children's HospitalUttoxeter RoadDerby DE223DTUK

Background:Upper arm composition is a reflection of body protein and calorie ***,there is a paucity of data on upper arm composition of children from African countries,including *** study aimed to determine the composition of upper arm and nutritional status of school children in Abeokuta,nigeria and to compare with international reference *** sensitivity and specifi city of upper arm muscle area by height(UAMAH)as a nutritional assessment tool was also ***:Five hundred and seventy children aged 5 to 19 years were selected from seven schools using multistage random ***,height,mid-upper arm circumference(MUAC)and triceps skin fold thickness(TSF)were *** mass index,upper arm muscle area(UAMA),upper arm fat area(UAFA),fat percentage and UAMAH were ***:The TSF,UAFA and fat percentage were significantly higher in females than males at each age *** and UAMA were significantly higher in female children aged 10-14 years,whereas UAMA was significantly higher in male children aged 15-19 *** and UAFA of the children were lower than those of Americans but similar to those of Zimbabweans,and higher than those of *** sensitivity and specifi city of UAMAH for detecting wasting were 80.8%and 63.9%,respectively,whereas the corresponding values for stunting were 32.2%and 58.2%,***:The school children studied have a combination of poor calorie and protein *** may be a valuable tool for complete evaluation of the nutritional status of school children.

关键词： nutritional status school children upper arm fat upper arm muscle

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Effects of Nitrogen Application and Weed Interference on Performance of Some Tropical Maize Genotypes in nigeria

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Pedosphere 2009年第5期19卷 654-662页

作者： J.O.AZEEZ Department of Soil Science and Land Management University of AgricultureAbeokuta(Nigeria)

Low soil nitrogen （N） and weed infestations are some of the major constraints to maize production in nigeria. A split-split plot experiment in a randomized complete block design with three replicates was established at two sites with different agroecological zones, Ikenne （Typic Paleudalf） and Shika （Typic Tropaquept）, in nigeria in 2002 and 2003 rainy seasons to investigate the responses of four maize genotypes （Oba super II, Low N pool C2, TZB-SR, and ACR 8328 BN C7） to N fertilizer applied at four rates, 0, 30, 60, and 90 kg N ha^-1, and three weed pressure treatments, no weed pressure （weekly weeding）, low weed pressure （inter-row weekly weeding）, and high weed pressure （no weeding throughout the growing season）. Growth and yield parameters of maize and weeds were taken at flowering and harvest. The results indicated that there was a significant reduction in maize leaf area, leaf area index, and photosynthetically active radiation due to weed interference at both sites. The application of nitrogen at 90 kg N ha^-1 significantly increased maize leaf area. Reductions in maize growth and yield at flowering and harvest were significant due to weed interference at both Ikenne and Shika, thus showing that the reductions in maize growth and yield due to weed interference were not ecological zone specific even though weed species and their seed banks may differ. Ameliorative management options could thus be the same in the two agroecological zones. Application of 90 kg N ha^-1 led to a significant increase in maize grain yield at Shika while there was no fertilizer effect at Ikenne on grain yield. There was no significant difference between 60 and 90 kg N ha^-1, suggesting that 60 kg N ha^-1 could be a possible replacement for the higher fertilizer rate at least for the identified maize genotypes. Low weed pressure treatment led to 26% and 35% reductions in maize grain yield at Ikenne and Shika, respectively, while 22% and 51% reductions, respectively, were observed due

关键词： maize growth maize yield N efficiency soil nitrogen weed pressure

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Source,depositional environment and maturity levels of some crude oils in southwest Niger Delta,nigeria

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Chinese Journal Of Geochemistry 2015年第2期34卷 224-232页

作者： Mudiaga Chukunedum Onojake L.C.Osuji S.Abrakasa Petroleum Chemistry Research Group Department of Pure and Industrial ChemistryUniversity of Port Harcourt Centre for Petroleum Geosciences Institute of Petroleum StudiesUniversity of Port Harcourt Department of Petroleum Engineering Niger Delta University

A suite of crude oil samples,that had not been previously characterized geochemically,was collected from two oil fields in the southwest Niger Delta *** saturate biomarkers were used to evaluate geochemical characteristics such as depositional environments,sources of organic matter and extent of biodegradation using gas chromatography-flame ionization detector and gas chromatography-mass *** of n-alkanes(Pr/Ph,and isoprenoide/n-alkanes ratios),the abundance of hopanes,oleanane skeleton and C27-C29 steranes in the oils indicate that they were formed from mixed sources(marine and terrestrial kerogen) deposited in an oxic paleoenvironment with no particular maturity *** parameters also permit the source grouping of the oils into two families.

关键词：尼日尔三角洲尼日利亚沉积环境西南部成熟度三角洲地区原油地球化学特征

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Assessment of GNSS zenith tropospheric delay responses to atmospheric variables derived from ERA5 data over nigeria

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Satellite Navigation 2023年第1期4卷 167-182,I0005页

作者： Ifechukwu Ugochukwu Nzelibe Herbert Tata Timothy Oluwadare Idowu Department of Surveying and Geoinformatics Federal University of Technology AkureAkureNigeria

Tropospheric delay is a major error caused by atmospheric refraction in Global Navigation Satellite System(GNSS)*** study evaluates the potential of the European Centre for Medium-range Weather Forecast(ECMWF)Reanalysis 5(ERA5)atmospheric variables in estimating the Zenith Tropospheric Delay(ZTD).Linear regression models(LRM)are applied to estimate ZTD with the ERA5 atmospheric *** ZTD are also estimated using standard ZTD models based on ERA5 and Global Pressure and Temperature 3(GPT3)atmospheric *** ZTD estimates are evaluated using the data collected from the permanent GNSS continuously operating reference stations in the nigerian *** results reveal that the Zenith Hydrostatic Delay(ZHD)from the LRM and the Saastamoinien model using ERA5 surface pressure are of identical accuracy,having a Root Mean Square(RMS)error of 2.3 mm while the GPT3-ZHD has an RMS of 3.4 *** the Zenith Wet Delay(ZWD)component,the best estimates are derived using ERA5 Precipitable Water Vapour(PWV).These include the ZWD derived by the LRM having an average RMS of 20.9 mm and Bevis equation having RMS of 21.1 mm and 21.0 mm for global and local weighted mean temperatures,*** evaluation of GPT3-ZWD estimates gives RMS of 45.8 *** study has provided a valuable insight into the application of ERA5 data for ZTD *** line with the fndings of the study,the ERA5 atmospheric variables are recommended for improving the accuracy in ZTD estimation,required for GNSS positioning.

关键词： ECMWF reanalysis 5(ERA5) Global navigation satellite systems(GNSS) Global pressure and temperature 3(GPT3) Modelling nigeria Zenith tropospheric delay(ZTD)

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Organic geochemical evaluation of the oil/gas-generative potential of organic matter in Cretaceous strata from the Lower Benue Trough,nigeria

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Chinese Journal Of Geochemistry 2010年第3期29卷 233-241页

作者： Minapuye I.Odigi Levi C.Amajor Department of Geology University of Port HarcourtPort Harcourt

An analytical procedure involving Rock-Eval pyrolysis of whole-rocks was adopted on fresh outcrop samples covering the three lithostratigraphic units in the Afikpo Basin of the Lower Benue Trough. Three petroleum systems are present in the Cretaceous delta frame: the Asu-River Group, the Eze-Aku Group and proto-Niger Delta sequences. The Afikpo Basin has been correlated to three petroleum systems in the Lower Congo Basin, Niger Delta and the Anambra Basin. The organic geochemistry of the shales, carbonaceous mudstones and coal beds show relatively moderate to high total organic carbon contents. The best potential hydrocarbon source rocks are the Eze-Aku Group and proto-Niger Delta shales, carbonaceous mudstones and coal beds where maturation was attained. The high total organic contents, thermal maturity and terrigenous characters of the Asu-River Group, Eze-Aku Group and proto-Niger Delta sediments, suggest the presence of a large amount of natural gas with a small quantity of oil accumulation. Variations in source rock facies were observed from one lithostratigraphic unit to another, and initial HI values as a function of TOC were proposed for each lithostratigraphic unit. The results also show that TOC, HI, OI, S2 and Tmax vary from older to younger rocks. The Tmax values discriminate the rocks into immature and mature source rocks. Source rocks with high Tmax suggest high geothermal gradient/or recycled organic matter. Also high Tmax and S2 yield indicate late and post maturity. Recycled organic matter is characterized by low Tmax. The principal source rocks for gas in the Afikpo Basin are the Eze-Aku Group and proto-Niger Delta beds deltaic systems, consisting mainly of III to IV kerogens with a subordinate amount of type II organic matter. Based on the obtained results, it is concluded that the Cretaceous shales, carbonaceous mudstones and coals in the Afikpo Basin of the Lower Benue Trough are capable of generating and expelling hydrocarbons in the case of su

关键词：岩石地层单位有机物质地球化学评价尼日利亚尼日尔三角洲白垩系热成熟度含油气系统

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Petrophysical characterization and 3D seismic interpretation of reservoirs in the Baris Field,onshore Niger Delta Basin,nigeria

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Energy Geoscience 2023年第1期4卷 103-116页

作者： Boris B.Bate O.A.Boboye K.F.Fozao Edwin Ayuk Ndip Nancy O.Anene Petroleum Geoscience Unit Department of GeoscienceInstitute of Life and Earth SciencePan African UniversityUniversity of IbadanIbadanNigeria Department of Petroleum Engineering School of Engineering(NAHPI)University of BamendaCameroon Department of Geology University of BueaCameroon

In order to evaluate the petrophysical properties,characterize the structural framework and determine the hydrocarbon in place of potential reservoirs in the Baris Field,onshore Niger Delta Basin,nigeria,3D seismic and well log data from the field were collected and interpreted using Geographix and Petrel *** reservoir zones B2 and B5 were identified having porosity ranging from 21%to 22%,permeability from 235 to 523 mD and water saturation from 16%to 28%.Petrophysical parameters show that the two zones are good reservoirs and highly *** interpretation revealed the presence of six listric faults,two major faults(F1 and F2 trending in the northwestesoutheast direction)and four minor faults(F3,F4,F5 and F6).Faults 3,4 and 5 trend in the same direction as the major faults,while fault 6 trends in the northeastesouthwest *** major horizons were identified,and they correspond to the two reservoir tops(B2_top and B5_top).Roll-over anticlinal structures between the two major listric faults were *** depositional environment of the Reservoirs B2 and B5 have been deciphered to be of a barrier bar or crevasse play and the trapping mechanism in the Baris Field is a four-way structural *** and GIIP for the two zones have been estimated with the zone B5 more prolific with a STOOIP and GIIP of 7.98MMSTB and 12.77MMMSCF respectively.

关键词： Petrophysical properties Reservoir quality Listric faults GIIP STOOIP

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Investigating unsafe behaviours in traffic conflict situations:An observational study in nigeria

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第5期6卷 482-492页

作者： Chinebuli Uzondu Samantha Jamson Frank Lai Institute for Transport Studies University of Leeds Leeds LS2 9JT UK Department of Transport Management Technology Federal University of Technology Owerri Owerri Nigeria

Although road users are aware of the possible risks of engaging in unsafe behaviours while driving,they continue to do *** behaviours often contribute to traffic incidents and crashes involving them and other road *** study set out to analyse the effect of road user type,location and time of day on unsafe driving behaviours observed in traffic conflict *** were collected by road side observation at three different locations in the eastern part of nigeria using the traffic conflict technique(TCT).This approach was adopted to overcome the inherent problems associated with reliable,inadequate and accessible crash data in *** total 946 traffic conflicts were observed and statistical testing showed that drivers were involved in one or more unsafe behaviours prior to these *** all unsafe behaviours observed,the incorrect use of indicators(13.3%) and tailgating(11.3%) were found to be the most prevalent,while road user type,location and time of day were found to be statistically associated with passenger scouting and other unsafe *** drivers were significantly more likely to engage in unsafe behaviours than vehicle *** are also more likely to engage in unsafe behaviours on straight ***,a greater number of these unsafe behaviours were observed during the peak *** is recommended that better road infrastructure,more effective regulations and enforcement,and proper road safety education could help improve traffic safety in nigeria.

关键词： Unsafe behaviour Traffic conflict Traffic safety Crash data

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