FACULTY OF SCIENCE
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Item Influence of colour on oviposition of mosquitoes breeding in artificial containers in Abeokuta, Ogun State, Nigeria(Researcher Connect Innovation and Impact Private Limited and MRI, 2008) Soniran, O.T.; Adeleke, M.A.; Adeyi, A.O.; Amusan, A.A.S.Nine species of mosquitoes were encountered during the study period. Ae. aegypti was the most abundant species constituting 75.39% of the total larvae collected followed by Culex quinquefasciatus (7.92%) and Aedes metallicus (6.83%). Other species were Aedes circumleteolus (6.54%), Culex dutoni (1.62%), Aedes albopictus (0.85%), Aedes taylori (0.74%), Aedes caballus (0.08%) and Aedes myormioformis (0.04%). Black containers harboured the highest number of larvae (32.12%) followed by yellow (24.01%), green (23.39%), red (15.40%) and white (5.00%) containers. Bamboo stumps bred the highest number of larvae (60.66%) followed by calabash gourd (26.04%) and plastic (13.27%).Item Gut Microflora and Microfauna of Earthworm Species in the Soils of the Research Farms of the University of Agriculture, Abeokuta, Nigeria(Taylor & Francis, 2008) Idowu, A.B.; Edema, M.O.; Adeyi, A.O.The present study investigated the microbial biomass (microflora and fauna) present in soil samples, gut sections and casts of earthworms collected from research farm areas on the campus of the University of Agriculture, Abeokuta. Keffia proxipora, Libyodrilus violacaeus and Hippoporera nigereae were the earthworm species identified from the soil samples. Isolated microflora included bacteria, yeasts and moulds while microfauna identified were protozoa and nematodes. For all samples of soil, casts and earthworms, the differences observed in counts of microflora and microfauna were significant at a level of p < 0.05. Casts stored for 2 weeks had higher pH and bacterial counts than those obtained from fresh castings. However, the pH values and nitrogen contents of both the fresh and stored casts were significantly higher than those for un-ingested soil samples. Among the earthworms identified, Libyodrillus violacaeus recorded the highest values of microflora and microfauna counts, significantly higher than values obtained for the other earthworm species. The hind gut of Libyodrillus violacaeus also had the highest bacterial, protozoal and yeast counts as well as total viable counts of microflora. Both micro-flora and fauna were found to increase in numbers during gut passage in all worms collected except for nematodes which were observed to reduce significantly in numbers during gut passage, with total disappearance in the mid and hind gut sections of some earthworm species.Item Distribution of bacteria and fungi in the earthworm Libyodrillus violaceous (Annelida: Oligochaeta), a native earthworm from Nigeria.(University of Costa Rica, 2006) Idowu, A.B.; Edema, M.O.; Adeyi, A.O.Earthworms are soil invertebrates that play a key role in recycling organic matter in soils. In Nigeria, earthworms include Libyodrillus violaceous. Aerobic and anaerobic bacterial counts, as well as fungal counts of viable microorganisms in soils and gut sections, were made on twenty L. violaceous collected from different sites on the campus of the University of Agriculture, Abeokuta, Nigeria. The samples were collected between April and November, 2002. Numbers of microorganisms were higher in castings and gut sections than in uningested soil samples. The guts and their contents also had higher moisture and total nitrogen contents than the un-ingested soils. Bacteria and fungi isolated from the samples were identified by standard microbiological procedures on the bases of their morphological and biochemical characteristics. Isolated bacteria were identified as Staphylococcus, Bacillus spp., seudomonas aeruginosa, Streptococcus mutans, Clostridium, Spirocheata spp.,Azotobacter spp., Micrococcus lylae, Acinetobacter spp., Halobacterium for bacteria. Yeast isolates were identified as Candida spp., Zygosaccharomyces spp., Pichia spp., and Saccharomyces spp while molds were identified as, Aspergillus spp., Pytium spp., Penicillium spp., Fusarium spp and Rhizopus spp. Of the five locations examined, the refuse dump area had the highest numbers of both aerobic and anaerobic organisms, followed by the arboretum while the cultivated land area recorded the lowest counts. The higher numbers of microorganisms observed in the gut sections and casts of the earthworms examined in this work reinforce the general concept that the gut and casts of earthworms show higher microbial diversity and activity than the surrounding soil. Rev. Biol. Trop. 54(1): 49-58. Epub 2006 Mar 31.Item Capture, Restraining and Transport of Wild Animals(Ibadan University Press, 2016) Adeyi A.O.Item Assessing Wildfire Occurrence in West Africa with Atmospheric Co₂ Removal(2025-06) Uzoma E.K.; Otunla T. A.; Nymphas E. F.; Ogunsola O. E.; Adeniyi M. O.The increase in wildfire occurrence is one of the consequences of the recent global temperature rise. Understanding wildfire occurrence in West Africa under atmospheric carbon dioxide removal is significant because of its implications on climate systems, ecosystems, agriculture, and socioeconomic development. This study projected the impacts of atmospheric carbon dioxide removal on fire occurrence in West Africa by analyzing the CNRM ESM1 C1 model output for the Carbon Dioxide Removal Model Inter-comparison Project (CDRMIP). Four climatological periods–1990–2019 (reference period), 2040 – 2069, 2070–2099 and 2100-2129 were analyzed using four fire indices. The periods 2040–2069, 2070–2099, and 2100–2129 have 42%, 45.9%, and 49.4% of “No Fire” category among other categories, respectively, with the Lebanese Index. With Mark 4 Grassland Fire Danger Index, a low category of fire risk is also predominant at 95.6%, 96.4%, and 66.1% for 2040–2069, 2070–2099, and 2100–2129, respectively. None of the indices projected a case of high, very high, or extreme risk in any period. “Low risk” category is predominant with all indices, particularly in Cote D’Ivoire, Ghana, Burkina Faso, Togo, Benin, and Nigeria. The low-risk category for fire occurrence during carbon dioxide removal in West Africa suggests a favorable outcome for the region’s ecosystems, agriculture, and communities. The study highlights the potential benefits of CDR beyond carbon removal, such as enhanced resilience, sustained productivity, and reduced vulnerability to climate-induced hazards like wildfires.Item Wind Characteristics and Potentials of Two-Parameter Weibull Distribution and Maximum Entropy-Based Distribution Functions at an Equatorial Location(2022) Otunla, T.A.; Umoren A. K.Thorough knowledge of the wind characteristics and variations are of great importance in the development of wind energy resource in any location. This study examines the wind characteristics and assess the potential of two distribution functions in a low wind equatorial region of West Africa. High resolution wind speed and direction data were obtained from a site in Nsukka, a location chosen in the region of study. Diurnal, seasonal and annual variations of both the wind speed and directions were examined. The potentials of two-parameter Weibull distribution and another distribution function based on Maximum Entropy principle (MEP) were assessed using R2 and root mean squared error (RMSE). The results indicated that day-time is windier than night-time. The transitions months of February, March and April have the highest wind speed. The dry season has greater energy potential than rainy season. The predominant wind direction lay within the sectors: South-South-West and East. The predominant wind sector for February, March and April is South-East. The R2 for daily, sub-seasonal day-time and night-time, monthly, and annual ranged between 0.90 and 0.99 for both MEP-based and Weibull distributions. The daily, sub-seasonal day-time and night-time, monthly, and annual RMSE also ranged between 0.011 to 0.075 for MEP-based and Weibull distribution respectively. Thus, both MEP-based and Weibull two-parameter distribution functions can be used to model wind data at the location of study.Item Variability and Probabilistic Extremes of Some Climatic Elements over Ibadan(2008) Otunla, T.A.; Oladiran, E. O.; Adeniyi M. O.Data on different climatic elements, like monthly rainfall monthly mean relative humidity, monthly lowest relative humidity; monthly mean temperature, monthly mean maximum and minimum temperatures with their monthly extremes values and monthly mean prevailing wind speeds over Ibadan for the months of January through to December during the period of 1979 through to 2005 have been considered to study their variability and to determine the probabilistic extreme values of these elements. The probabilistic extremes values have been computed for 3 time scales: In 1 year out of 4 years, in 1 year out of 10 years and in 1 year out of 25 years- representing relative more frequent events, moderately extreme events and extreme events, respectively.Item Simple and Reliable methods of Estimating Ground Heat Flux at a Tropical location in Nigeria(2019) Otunla, T.A.; Oladiran, E. O.Ground heat flux (Go) plays an important role in the partitioning of energy budget at earth’s surface. The estimates of G0 are required as part of boundary conditions by all general circulation models. In this work, reliability of four simple and computationally cheap models was tested against a more complex and reliable model as the reference. The simple models selected for investigation are: Simple measurement (SM), Percentage of net radiation (PR), Universal function of net radiation (UR), and Linear function of net radiation (LR) models. Force restore model (FR) was used as the reference model. The data of soil temperature measured at the surface and 0.05 m depth, soil heat flux, measured at 0.05m, and net radiation were obtained from Nigerian Micrometeorological Experiment, Ile Ife. Force restore model was first calibrated with direct measurements for soil heat flux at 0.05 m depth with satisfactory result before it was employed to generate reference G0 estimates. Estimates of SM, PR, UR and LR were compared with FR using simple statistics of coefficient of determination (R2), slope, intercept, root mean square error (RMSE) and mean bias error (MBE). The SM model reproduced the day-time and night-time variations of G0 better than all the models that parameterized G0 as a function of net radiation (R2, slope, intercept, RMSE and MBE values of 0.85, 0.87, 3.43W/m2, 32.69, W/m2, -3.70 W/m2 respectively). This model however requires measurement of both soil heat flux and temperature. The LR model generated the best estimates of Go out of all the models that utilized net radiation measurements (R2, slope, intercept, RMSE and MBE values are 0.60, 0.58,4.55 W/m2, 53.81 W/m2 and 3.60 W/m2 respectively) while UR model is the worst. The LR model, though depend only on one measurement, requires site-specific calibrations and can therefore be deployed for gap filling where SM model cannot be used. "Item Impact of Soil Heat Flux Attenuation on Surface Energy Balance Closure(2012) Otunla, T.A.; Oluwafemi, S.M.In surface energy balance (SEB) measurements, ground heat flux (G) is either reconstructed from soil temperatures using analytical method or from the combination of calorimetric method with soil heat flux measured at 0.05 cm depth or more. Soil heat flux signal attenuation is known to increase with depth. This work intends to investigate the impact of this attenuation, which arises from the placement depths of soil temperature and heat flux plates sensors on SEB closure. Ground heat flux was reconstructed from soil heat flux and temperature measurements at two separate depths of 0.05 and 0.10 cm using calorimetric and analytical methods. The two data sets of G were combined with other SEB components to quantify the impact of placement depth of the soil sensors on SEB closure as a change in residual of SEB measurements (ΔRes). For the calorimetric method, the lowest value of ΔRes in the morning hours was -10W/m2 and the peak value during the daytime was +43W/m2. The values of ΔRes fluctuate between ±20 W/m2 in the morning hours and ±42W/m2 during the daytime for the analytical method but with a greater tendency towards positive ΔRes. Thus, SEB closure decreased with the increasing placement depth of the soil sensors, especially during the daytime. The implication of all these results is an irrecoverable signal loss in the soil heat flux as the placement depth of the sensors increases especially during the daytime.Item "Evaluation of soil thermal diffusivity algorithms at two equatorial sites in West Africa"(2021) Otunla, T.A.; Oladiran, E. O.This study presents comparisons between six algorithms used in the calculation of apparent thermal diffusivity (Kh ) of the topsoil during measurement campaigns conducted at two equatorial sites. It further investigates the effects of transient and seasonal variations in soil moisture content (i) on the estimation of Kh. The data used comprise soil temperatures (T) measured at depths of 0.05 m and 0.10 m, and i within the period of transition from the dry season to the wet season at Ile Ife (7.55° N, 4.55° E), and for the peak of the wet season at Ibadan (7.44° N, 3.90° E). The thermal diffusivity, Kh, was calculated from six algorithms, of: harmonic, arctangent, logarithmic, amplitude, phase, and conduction-convection. The reliability of these algorithms was tested using their values to model T at a depth of 0.10 m, where direct measurements were available. The algorithms were further evaluated with statistical indices, including the empirical probability distribution function of the differences between the measured and modeled temperatures (DT). The maximum absolute values of DT for the six algorithms investigated were: 0.5°C, 0.5°C, 0.5°C, 1°C, 1°C and 1°C, respectively. Kh showed an increasing trend as i increased from the dry season to the peak of the wet season, with R2 = 0.70 for the harmonic algorithm. The accuracy of all of the algorithms in modeling T reduced with transient variations of i. The harmonic, arctangent and logarithmic algorithms were the most appropriate for calculating Kh for the region of study. The empirical relation between i and Kh and the values of Kh obtained in this study can be used to improve the accuracy of meteorological and hydrological models.