Ehinlafa, O. E., Abdulsalam et al. (13 contributing authors)
In this study, f o F2 variability diurnally, seasonally and annually was investigated during a Low Solar Epoch (LSE) over Ilorin (latitude 8.31°N, longitude 4.34°E, dip latitude 2.95 o ), a low latitude station along the equatorial anomaly trough. The percentage variability index () was used for the analysis. The percentage variability index () is lowest during the day (2-17%); increases during night to (8-55%); and attained the highest magnitude during pre-sunrise phase (17-68%), for the period of LSE. Two major peaks were noticed in V R : the pre-sunrise peak, which is higher, and the post-sunset peak. Annually, peaks at 44% for the pre-sunrise phase, and 37% for the post-sunset phase, during the LSE. The rapid electron drift away from the equator coincides with subsequent rise in the percentage variability index immediately after sunset for all the seasons.
Critical frequency (foF2)Variability index () 
Odusina, B. O., Oyeyemi et al. (13 contributing authors)
Olax manii stems were collected in Ikire, Osun State, Nigeria. Using the hydrodistillation process, essential oil was extracted from the stem of Olax manii. To ascertain the chemical composition of the essential oil, Gas chromatography mass spectrometry (GCMS) technique analysis was employed. Using doses ranging from 100 to 25 µg/ml, the antioxidant properties of the essential oil were examined using the 2, 2-Diphenyl-1 picryl hydroxyl (DPPH) radical scavenging activity method. The results of the Gas chromatography mass spectrometry (GC-MS) analysis indicated that the main chemical constituents were squalene (6.18 %), amyrone (4.49%), and neophytadiene (4.22 %). The minor constituents were identified as limonene (0.23 %), caryophyllene (0.31 %) and phytol (1.62 %). The essential oil radical scavenging activity at a concentration of 100 mg/ml was compared to the standard ascorbic acid at the same concentration and it revealed that the essential oil exhibited a significant percentage radical scavenging activity of 78.52 %. The percentage radical scavenging activities increased with increase in concentrations of the essential oil. The Essential oil constituents which possess antioxidant activities could be responsible for the antioxidant activities and ethnomedicinal uses of Olax manii.
Oguntunde, B. O., Ologunye et al. (7 contributing authors)
The mandatory wearing of face masks orchestrated by the COVID-19 pandemic has brought some complexities to the ability of face recognition systems in identifying such faces. Thus, this study examined the performance of some selected machine learning algorithms: Convolutional Neural Network (CNN), Linear discriminant analysis (LDA), Logistic Regression (LR), K-Nearest Neighbour (KNN), Support Vector Machine (SVM), Naïve Bayes (NB) and Decision Tree (DT) for the recognition of masked and unmasked human faces; and developed a face recognition system based on the algorithm with the best performance. The dataset was composed of 11,792 masked and unmasked facial images collected from Kaggle online repository. The set was divided into 70%, 20% and 10% respectively for training, testing and validation each for the masked and the unmasked face images. The images were augmented randomly for training, with some rotated 30 degree, some zoomed 20%, some shifted horizontally by 10% in width, some shifted vertically by 10% in height and some flipped horizontally. The performance analysis of the algorithms presented accuracies of 99% and 99% for the CNN; 93% and 98% for LDA; 93% and 93% for LR; 86% and 78% for the NB; 70% and 70% for the KNN; 64% and 45% for the DT; and 92% and 98% for the SVM respectively for training and cross validation. Overall, the CNN recorded the highest recognition accuracy. Thus, a CNN user-friendly face recognition, system was developed, and tested with a number of real-life human masked and unmasked faces which showed excellent recognition performance. The implementation was carried out with appropriate Python machine libraries. The developed system could be very useful for access control and surveillance. Therefore, this study recommends the adoption of the developed systems for face recognition-based security system.
Balogun, Oluwatimilehin B.1, and Osazuwa Isaac B.2
Physical geodetic survey of the Nigeria landmass was undertaken with the aim of furnishing engineers and scientists with vital geodetic information which have not been adequately available but required for the development of a standard national economic framework. The basic data used for the study were the absolute gravity field values, and the recorded coordinates and elevations at the Primary Gravity Network of Nigeria (PGNN) base stations. The absolute gravity data were processed using the appropriate mathematical and computational procedures to deduce geodetic information which include geoid undulation, height above the geoid, deflections of the vertical, distance from the earth’s centre of mass to the reference ellipsoid and geoid, and the gravity potential value at the geoid. Comparison was also made between the WGS’84 and the geoid in the study area. Geoid undulations were found to range from 16.53 to 28.35 m and the deflections of the vertical ranged between 0.738685 to 10.28328 arc second. Height above the topography ranged from -16.38 m in Warri to +1257.13 in Jos. The distance from the earth’s centre of mass to the WGS’84 reference ellipsoidal surface was maximum at Oron (6377988.04 m) and least at Illela (6376941.31 m). Similarly, the distance from the earth’s centre of mass to the geoid was also maximum at Oron (6378008.39 m) and minimum in Illela (6376961.659 m). The interpolation of the distances from the earth’s centre of mass to the spheroidal surface at each base station gave the definition of the WGS’84 ellipsoid over the continental Nigeria landmass while the interpolation of the distances from the earth’s centre of mass to the geoidal surface gave the definition of the geoid over the continental Nigeria landmass. The average gravity potential at the geoid was evaluated as 62375050.41 m 2 s -2 . The geoid over the continental Nigeria landmass was found to be comparably smooth as the WGS’84 ellipsoid over the region though they differ in terms of vertical separation. The quantitative difference in mGal corresponding to the vertical separation between the WGS’84 reference ellipsoid and the geoid was computed as 6.8042 mGal. The values of the deflections of the vertical at each station of the PGNN gave the angular correction to be applied when combining satellite-based ellipsoidal measurements and geoid-based physical geodetic measurement. Based on the significant range of the deflections of the vertical across the continental area of Nigeria, it was concluded that the physical structure of the lithosphere beneath the study area must be highly complex and heterogeneous.
Physical geodetic survey Primary Gravity Network of Nigeria (PGNN)geoid undulationsdeflections of the vertical
Egwu, H. A., Yilwa et al. (14 contributing authors)
Hyptis suaveolens , an aromatic plant commonly called Daddoya-ta-daji in Hausa language, is traditionally used as medicine and food. It is used as stimulant, antirheumatic, carminative, against parasitic diseases, headaches, infection of the uterus, stomach, and skin diseases. It is found growing in both oil polluted and non-oil polluted environment. Oil pollution of land is a challenge due to the presence of heavy metals and volatile organic compounds which are harmful to crops and plants. This study investigated the phytoconstituents of the methanol leaf extract as well as antimicrobial activities of Hyptis suaveolens collected from polluted and unpolluted sites. Methanol leaf extracts of H. suaveolens were screened for crucial phytochemicals using standard methods. The in vitro antimicrobial activity was carried out using agar disc-diffusion method by Yahaya et al . (2018), using Mueller Hinton agar medium and potatoes dextrose agar in petri plates seeded with clinical isolates of Escherichia coli, Salmonella typhi, Shigella sp, Staphylococcus aureus (bacteria), Candida albicans and Aspergillus niger (fungi) respectively, and the zone of inhibition determined. The phytochemical results showed that methanol extract of both the polluted and non-polluted H. suaveolens leaves exhibited the presence of some number of bioactive compounds. Gas Chromatography–Mass Spectrometry (GC-MS) of polluted and non-polluted leaves of H. suaveolens identified 13 and 21 compounds, respectively such as Octadec-9-enoic acid, 2-Ethylacridine, Methyl ester, Tetracyclo [4.4.1.1(7,10).0(2,5)] dodec-3-en-11-ol, 1,2-Diphenyl-1-isocyanoethane and 7-Isopropyl-1, 1, 4a-trimethy l-1,2,3,4,4a,9,10,10 aocta -hydrophenanthrene. These chemical compounds are considered biologically and pharmacologically important. The results from assessment of the antimicrobial potential of H. suaveolens (L.) on pathogenic microorganisms showed that the pathogenic microorganisms revealed inhibition zones ranging from 6 to 18 mm. This data indicates that the unpolluted methanol extract of H. Suaveolens exhibits a higher bioactive potential compared to the extract derived from polluted leaves. This disparity suggests that oil pollution may have a detrimental impact on the biochemical properties of the plant.
Femi-Olabisi, Fehintoluwa Joy, Komolafe et al. (8 contributing authors)
The toxicological effects of ethanolic extract of Parquetina nigrescens leaves (EEPNL) on letrozole-induced polycystic ovarian syndrome (PCOS) in Wistar rats were evaluated. Twenty female Wistar rats (170.81 ± 5.25g) were randomly assigned into 5 groups (A - E) of four animals each. Animals in group A received 1 ml of distilled water and group B-E received 1mg/kg body weight of letrozole daily basis for a period of 21 days orally. The letrozole-treated groups, B-E, were then administered 1 ml of distilled water, co-administration of 7.14mg/kg of metformin and 2mg/kg clomiphene citrate (reference drug), 50 mg/kg b.wt of EEPNL and 100 mg/kg b.wt of EEPNL respectively for a period of 14 days. The animals were sacrificed 24 hours after the last treatment dose and the blood obtained via jugular puncturing was used in determining some toxicological indices such as liver function indices (albumin, bilirubin, globulin and total protein), kidney function indices (Urea, uric acid and creatinine), and enzyme assay (Alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase). The result revealed mild alterations in the parameters under studied in this work and this suggests that the ethanolic leaf extract of Parquetina nigrescens at doses investigated may be safe when used in the treatment of PCOS.
C. O. Tinubu, O. J. Falana, D. O. Aborisade et al. (5 contributing authors)
Application layer Distributed Denial of Service (DDoS) attacks are becoming increasingly prevalent on Internet based web services. Severe HTTP GET flood attacks are often launched by attackers, wherein web servers become overwhelmed with superfluous GET requests. This exhausts the processing and connectivity resources of the servers, hence resulting in service failures. As availability of services is key to online service providers, this work presents a behavioral based detection system named 'DDoSDetect' for HTTP GET flood attacks. In DDoSDetect, a traffic monitor tracks incoming GET requests sent to the server. Four distinct behavioral features such as the rate of requests, time interval between successive requests, session rate and the frequency of requests on a web page, are employed to analyze user's behaviors. A detection unit driven by three phases: LRP (Legitimate Request Phase), IRP (Illegitimate Request Phase) and SVM-RC (Support Vector Machine-Request Classifier) is designed to intelligently classify incoming GET requests. Illegitimate GET requests are dropped while legitimate requests are forwarded to the web server. DDoSDetect is implemented and results obtained from evaluation processes signify the effectiveness of the system towards the mitigation of HTTP GET flood attacks. Also, the system is real time and capable of handling sophisticated attacks.
Application layeravailabilityDDoS attacksHTTP GET floodInternet
