FACULTY OF SCIENCE
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Item Impact of the total solar eclipse of 29 March 2006 on the surface energy fluxes at Ibadan,Nigeria(2012) Nymphas,E.F.; Otunla,T.A.; Adeniyi,M.O.; Oladiran, E.O.This paper document the impact of the total solar eclipse (97.4%) of 29 March 2006 on the surface energy fluxes at Ibadan, Nigeria (longitude4.561E, latitude7.551N), a tropical location. The surface energy (determined by the BREB method) was found to be grossly affected by the eclipse. The latent heat and net radiation (Rn) lagged the sensible heat by 11 min in totality. The sensible heat lagged the latent heat and Rn by 6 min before it start to increase after the totality phase of the eclipse while global radiation (Rg) lagged Rn by 7 min. The sensible heat reversed sign reaching a value of _1.02 Wm_2 during the total phase of the eclipse while the latent heat dropped by 89.7%. All the radiation fluxes (global radiation, Rg, net radiation Rn, temperature and soil heat flux) measured during the eclipse event were significantly affected by the sudden ‘cutoff’of the solar irradiation.There was a 95% decrease in Rg, while Rn dropped from 354.3Wm_2 to _11.7 Wm_2.Item TLC phytochemical screening in some Nigerian loranthaceae(Academic Journals, 2010-07) Wahab, O. M.; Ayodele, A. E.; Moody, J. O.The phytochemical screening of specimens of the family Loranthaceae collected from the field was carried out with a view to ascertaining chemical constituents present and determining their importance in the taxonomic delimitation of the taxa. Thirty field collections from various localities were screened for secondary metabolites such as alkaloids, anthraquinones, terpenoids and ketones using thin layer chromatography (TLC). Most of the samples tested slightly positive for alkaloids, anthraquinone-related compounds, terpenoids and terpenoidrelated compounds but ketonic compounds were of rare occurrence in all the samples. The chemical profile was useful in separating the collections of Phragmanthera from the other two genera while the collections of Globimetula were found embedded in Tapinanthus. The secondary metabolites obtained however showed the relative affinity of the Nigerian species of Tapinanthus. It is concluded that chemical characters may only be used as supporting evidence in the identification and delimitation of the taxa.Item Foliar epidermal studies in the family Bignoniaceae Juss. in Nigeria(Academic Journals, 2008-02) Ugbabe, G. E.; Ayodele, A. E.Comparative studies have been carried out on the leaf epidermal features of eleven species of the family Bignoniaceae in Nigeria. The species are relatively uniform in the qualitative macro morphological characters except in the leaf shape, which varies from ovate, elliptic, oblong-elliptic, oblong, oblanceolate to obovate-lanceolate. A more constant macro character for the species is the leaflet length /leaflet width ratio, which ranges from 2:1 to 4:1. The epidermal morphology of the adaxial and abaxial surfaces of the species was studied with the light microscope. The epidermal cells are polygonal, irregular or both. Anticlinal walls are straight, curved or undulate/ wavy. Leaflets of all species are hypostomatic with stomata restricted to the abaxial surface. The Anomocytic stomata type is most prominent except Kigelia africana, which has diacytic stomata. Striae are present on the adaxial surface of Oroxylum indicum and abaxial surface of Spathodea campanulata. Knobs are present on the abaxial and adaxial surfaces of Markhamia lutea, Markhamia tomentosa, abaxial surface of Stereospermum kunthianum and adaxial surface of Tabebuia rosea. Other features of the epidermis that show variation include stomatal size, shape and frequency. Epidermal cell shape, anticlinal wall undulation, striation on the epidermis, stomata type, distribution and stomata index are of taxonomic importance in the family while epidermal size and number are of little diagnostic value. The significance of these observations is discussed in relation to the taxonomy of the family.Item The pollen morphology of Nigerian bignoniaceae Juss(2007) Ugbabe, G. E.; Ayodele, A. E.; Okogun, J. I.; Inyang, U. S.The Pollen grains of eleven species of the Bignoniaceae represented in Nigeria have been studied by the light Microscope. The pollen grains are mostly circular or elliptic. The circular ones include those of Crescentia cujete Linn. Markhamia tomentosa (Benth.) K.Schum., Newbouldia laevis Seem., Oroxyllum indicum Vent., Spatliodea campanulata P.Beauv., Stereospermum acuminatissimum K.Schum., Stereospermum kunthianum Cham., and Tabebuici rosea (Berthol) DC. while the Elliptic ones are: Kigali a africana (Lam) Benth., Markhamia litlea (Benth.) K.Schum. and Tecoma stans (Linn ) H.B & K. and the shape/class range from prolate, sub-prolate to prolate spheroidal. The Prolate ones are Kigelia africana, Markhamia tomentosa, and Tecoma stans; the Subpralate types includes those of Crescentia cujete, Markhamia lutea, OroxyUum indicum. Spathodea campanulata and Stereospermum acuminatissimum; while the Prolate-Spheroidal types are those of Stereospermum kunthianum and Tabebuia rosea. They are either tefra- colporate or tri-colporate. The pollen of Crescentia cujete is Tetra-Colporaie while tiic others are Tri-colporate (Tri-colporate = Pollen grains with three ectocolpi;). The different pollen types are useful in the identification of the Nigerian Bignoniaceae.Item Morphological studies in lycopersicon esculentum Mill. lines in Southwestern Nigeria(Asian Network for Scientific Information, 2007) Lawal, O. J.; Ayodele, A. E.; Chukwuka, K. S.Morphological studies of thirty lines of Lycopersicon esculentum Mill were carried out in order to find out characters, which may be used for the delimitation of the cultivars in Nigeria. The quantitative and qualitative characters studied include leaf type, leaf length, leaf shape, leaf breadth, petiole length, number of leaves per plant, number of leaflets per leaf, number of serration per leaflet days taken for germination, days taken for first picking, stem diameter, fruit diameter, fruit shape, fruit colour, stem type, stem colour, stem texture, leaf arrangement and growth habit. Morphological characters that indicate close affinity amongst the cultivars include leaf type, leaf base, leaf shape, leaf apex, leaf margin, leaf arrangement stem colour, fruit colour, number of calyx and corolla. However, the features that are taxonomically relevant in the delimitation of lines of L. esculentum are fruiting habit, fruit shape and presence or absence of ridges on the fruits. The three cultivars recognized are Ibadan local, hybrid and Roma VF. Numerical analysis of the qualitative and quantitative characters data using cluster analysis-average linkage, single linkage, complete linkage and centroid method delimit all the thirty lines into three major groups which conform to the results of the morphological analysis.Item The medicinally important leafy vegetables of south western Nigeria(2005) Ayodele, A. E.This paper focuses on twenty eight medicinally important leafy vegetables documented from the South western part of Nigeria. It also highlights their medicinal importance in the treatment of minor ailments as well as their sources. The family Compositae (Asteraceae) contained the highest number of plants followed by the Cucurbitaceae, Malvaceae and Solanaceae. Sixty eight percent of the documented vegetables are cultivated, eleven percent is usually obtained in the wild while twenty one percent is either cultivated or obtained from the wild. The need for concern on the conservation of genetic resources of these plants (especially those in the wild) is stressed in order to safeguard them for future generations and avoid their genetic erosion. The establishment of a gene/seed bank for vegetables is advocated.Item Comparative epidermal morphology of Nigerian species of alchornea (euphorbiaceae)(1999) Comparative epidermal morphology of Nigerian species of alchornea (euphorbiaceae)The leaf epidermal morphology of the three Nigerian species of Alchornea (Euphorbiaceae) has been studied using light microscopy. Epidermal cells arc irregular with undulate to sinuate anticlinal walls. The abaxial and adaxial walls of A. cor difolia and A.floribunda respectively arc characterized by the presence of knobs on them. All taxa have paracytic stomata. However, while A. cordifolia and A. laxiflora arc amphistomalic, A floribunda is hyposlomatic. Trichomcs arc simple, unicellular and unscriate in A.floribunda and A. laxiflora while stellate trichomcs with two to eight radiating arms are present in A. cordifolia. All taxa except A . laxiflora are entirely smooth on the adaxial surface. An indented dichotomous key based on the features of light microscopy is presented for die identification of die species.Item Fractional integration and structural breaks in bank share prices in Nigeria(Elsevier, 2015) Gil-Alana, L. A.; Yaya, O.S.; Adepoju, A. A.The paper employs both fractional integration and structural break techniques in studying the daily share prices structure of the banking sector in Nigeria. Our data span between 2001 and 2012, covers periods before and after the global financial crisis. The results obtained using both parametric and semi parametric methods indicate little evidence of mean reversion since most of the orders of integration are equal to or higher than1. Long memory is found in the absolute and squared return series. The possibility of structural breaks is also taken into account and the results show a different number of breaks depending on the bank examined. In general, an increase in the degree of dependence across time is noticed, and the most common break took place in December 2008, probably being related with the world financial crisis affecting also the banking system in NigeriaItem Guinea worm disease and its persistence in some rural communities in Nigeria(2007) Morenikeji, O. A.; Alade, A. O.; Odaibo, A. B.Studies were carried out in six villages of Ogun State, Nigeria from January to December 2004 to identify the reasons for the persistence of guinea worm disease in spite of eradication measures. Pre-tested structured questionnaires were administered to 250 head of households in the endemic villages to assess their knowledge attitude and practice (KAP) in the management of guinea worm disease. The overall prevalence of infection for the study-period was 1.0%. 96.0% of the respondents depended solely on ponds for drinking water during the dry season. 80.0% of the respondents had been infected before 68.0% think that the disease is caused by spiritual attack, while 4.0% associated the disease to drinking bad water. 77.5% did not know if it is possible to prevent the disease. It was observed that immigrant farm labourers and apathy on the part of eradication officials may play vital roles in the transmission of the disease in the area. This study shows that there is need to ascertain and specifically address reasons for the persistence of the disease in areas still endemic.Item Use of block inversion in the 2-D interpretation of apparent resistivity data and its comparison with smooth inversion(Elsevier, 2000) Olayinka, I. A.; Yaramanci, U.The ability of a block inversion scheme, in which polygons are employed to define layers and/or bodies of equal resistivity, in determining the geometry and true resistivity of subsurface structures has been investigated and a simple strategy for deriving the starting model is proposed. A comparison has also been made between block inversion and smooth inversion, the latter being a cell-based scheme. The study entailed the calculation (by forward modelling) of the synthetic data over 2-D geologic models and inversion of the data. The 2-D structures modelled include vertical fault, graben and horst. The Wenner array was used. The results show that the images obtained from smooth inversion are very useful in determining the geometry; however, they can only provide guides to the true resistivity because of the smearing effects. It is shown that the starting model for block inversion can be based on a plane layer earth model. In the presence of sharp, rather than gradational, resistivity discontinuities, the model from block inversion more adequately represents the true subsurface geology, in terms of both the geometry and the formation resistivity. Field examples from a crystalline basement area of Nigeria are presented to demonstrate the versatility of the two resistivity inversion schemes.