ABSTRACT
This study was carried out to determine and compare the phytochemical and antioxidant activities of Allium fistulosum, Bryophyllum pinnatum, Cymbopogon citratus and Heinsia crinita. The leaves were washed, dried and powdered. The powdered leaves were macerated in methanol for forty-eight hours (48hrs) after which the filtrate obtained was concentrated in an oven at 40oC. The methanol extract of the leaves, were then screened for phytochemicals. Antioxidant activities of the leaf extracts were ascertained using the ferric reducing antioxidant power (FRAP) method and hydrogen peroxide scavenge assay. Results show that A. fistulosumB. pinnatum, C. citratus and H. crinitacontains phytochemicals including flavonoids, reducing sugars, terpenoids, steroids, saponins, alkaloids, tannins, amino acids, proteins and cardiac glycosides. Fixed oils were absent while saponins were present in all fourextracts. FRAP and hydrogen peroxide scavenging assay revealed the potent antioxidant activity of all plant extracts. However, B. pinnatum showed the highest ferric reducing antioxidant power, followed by H.crinita, A.
fistulosum and C. citratus, at varied concentrations of ferric cyanide. H. crinita at varied concentration of Hydrogen peroxides, revealed the highest percentage scavenging ability followed by A. fistulosum, B. pinnatumand then C. citratus. This study has revealed that the leaf extracts of A. fistulosum, B. pinnatum, C. citratus and H.crinita possess potent antioxidant activity, phytochemical and nutritional benefits, with B. pinnatum having the highest phytochemical and nutritional content.It also supports their use in folk medicine for the management of diseases. Further research should be carried out to ascertain specific active principles in these plants.
Keywords: Phytochemicals, Antioxidants, Hydrogen Peroxide scavenging, ferric reducing antioxidant power
ABSTRACT
Wavelets transforms (WT), are distinctive set of orthonormal basis functions specially formed for filtering and trend prediction of signal data. One key advantage of WT tool is that it possesses the capacity to cater for both temporal and spectral representation of signal components, simultaneously. However, a key challenge in exploring WT for optimal signal processing is in its ability to determine the right threshold value, which facilitate in the estimation noise level from a noising signal or data. If the chosen threshold value is too big, then some essential components of the signal features may be filtered out. On the other hand, if the chosen threshold value is too small then a substantial quantity of noise will still present in the data. In this work, the optimal signal denoising ability of four thresholding value selection measures, namely Rigrsure, Sqtwolog, Minimax and Heursure are examined and reported on measured signal dataset, under soft thresholding and hard thresholding. The performance of each threshold selection measure is also examined and presented in this work, using five different quantitative evaluation metrics. The metrics includes: the Signal to reconstruction ratio, Root square error, Pulse amplitude distortion, Standard deviation, and mean absolute error. The results reveals that soft thresholding category with Rigrsure repetitively outperforms all other selection rules per every performance metric after denoising, with the heuristic SURE (i.e. heursure) coming in second. The optimal practical signal processing methodology employed in this work can be explored by scientists, engineers and data analyst to trend noisy signal, characterize transient events, compress data and perform many other operations, especially in the area of signal preprocessing in medical imaging and telecommunication system networks.
Keywords: Wavelets, Measured noisy signal, Soft threshing, Hard thresholding, Thresholding selection rules.
ABSTRACT
Geoelectrical imaging of the subsurface to investigate the impact of flood injection on groundwater contaminants in a typical flood area in Benin City, Nigeria was carried out. The 2 – Dimensional electrical resistivity survey method for the subsurface imaging was done by engaging the Wenner array configuration using Petrozenith terrameter in the surface measurement. The vertical electrical sounding (VES) was also done by using the Schlumberger array configuaration to determine the depth to the aquifer layer. The DIPRO software and the RES2DINV software were used for the interpretation of the 2-D resistivity data. Physico-chemical analysis of water was carried out to test for the presence of heavy metals. From the VES result, the depth to the aquifer lies around 37.2m of resistivity of 17.3Ωm and the 2-D results showed the resistivity values for DIPRO from 40Ωm to 100Ωm and for RES2DINV from 12.7Ωm to 53.2Ωm respectively showing that the study area has groundwater potential. For the Physico-chemical analysis of water, the result showed the presence of heavy metals such as Nickel (0.09mg/l) and Chromium (0.26mg/l) which when compared with Nigerian Standard for Drinking Water quality (NSDWQ), were found to have exceeded the maximum permitted level, Nickel (0.02mg/l) and Chromium (0.05mg/l). As a result, it was obvious that the presence of Nickel and Chromium, in the Physico-chemical analysis, are likely the cause of the low resistivity
values observed in the 2-dimensional electrical resistivity survey results. Besides, both elements are harmful to human beings when ingested because they are carcinogenic, that is, they can cause cancer. Also the boreholes that are not close to the injection well do not have traces of heavy metals which further reveal that as one moves away from the injection well, contamination of groundwater is not obvious.
KEYWORDS: Geoeletrical, Contaminant, Imaging, Physico-chemical analysis
ABSTRACT
Over the years, developers have encountered some challenges with software development. Software researchers have been able to develop process models that cater to the different types of software application and if followed correctly can result in software that are delivered on-time, cost effective and conform to user’s needs. Knowing the right process model to use in software development can posed a challenge for software developers. This research deals with Software Development Process and briefly describes four process models which are: Waterfall Model, Spiral Model, Rapid Application Development (RAD) and Extreme Programming (XP), outlining their advantages and disadvantages and making a comparison to show the features and flaw of each model. These models were chosen because they represent the Tradition lifecycle models and the Agile process model.
KEYWORDS: Software development, Software Engineering, Software Lifecycle, Process Models
ABSTRACT
This paper deals with the development of expected cost model in a fixed lifetime inventory system. In this type of inventory, items in stock are expected to be used before the expiring date. The system consists of an age-wise profile of items (state space). The size of the space is directly proportional to the life of the items. Consequently, the inventory management is faced with lots of challenges otherwise item will be outdated, additional cost such as holding cost, shortage cost and ordering cost will be incurred. Optimal solutions to the fixed lifetime of perishable inventory problem cannot be realized in practice due to their computational complexity arising from the fact that exact formulation of the problem requires information on the age distribution of the items in inventory and the corresponding quantity of items of each age. Hence there is a gap between theoretical results and practical requirements for computational results. The purpose of this study is to minimize the proposed expected cost model, an interval of the optimal value of inventory level (s) was derived Hence we bridge the gap between theoretical results and practical requirements for computational results. The expected holding cost, expected shortage cost, expected outdates cost, ordering cost were computed and were applied to determine the expected cost for the fixed lifetime inventory system.
KEYWORDS: Probability of running out of stock, Expected holding cost, Expected outdate cost, Expected shortage cost, Optimum value of s, Uniform distribution.
ABSTRACT
This study was carried out to examine the profitability, viability and constraints of small scale catfish farming in Yenagoa Local Government Area of Bayelsa State. One hundred and twenty small scale catfish farmers were randomly sampled from twelve communities purposively selected from the study area. Data were collected with the aid of well-structured questionnaire augmented with scheduled interview and discussion with the respondents. Data were analyzed using descriptive analytical tools such as tables, frequencies and percentages. The results of the analysis showed that 90% of the farmers are males; majority fell within the age bracket of 26-55 years. Most of them are fairly educated, majority are married (73.4%) with a mean household size of six persons. The net profit technique was used to estimate the profitability level of the enterprise and benefit cost ratio was used to assess the viability of the venture, while ranking was used to analyze the problems faced by the farmers. The analysis estimated an average operating cost of N267,029.67; an average total fixed cost (depreciation) of N29,689.24 and an average net farm income of N577,367.42. This result showed that catfish farming is a profitable enterprise. The benefit-cost ratio was 2.95 which implied that for every one naira (N1) spent N2.95 was realised. High prices of fish feed and fingerlings, inadequate water supply, communal land ownership, inadequate extension services, lack of capital, diseases and pests were the top ranking constraints faced by catfish farmers. The study therefore suggests provision of conducive environment for sustainable cat fish production through provision of credit facilities, formulation and implementation of proper policies on aquaculture by the government and relevant stakeholders.
KEYWORDS: Cat Fish, Small- Scale, Profitability, Benefit-Cost Ratio, Yenogoa.
ABSTRACT
The demand for increased mobile phone subscribers require an efficient radio network planning that involves an accurate prediction of propagation loss. Although various empirical loss models are in use, they are suitable for a particular environment or a specific cell radius. The tuning of a model is a process in which the parameters of the theoretical propagation model are adjusted with the help of measured values obtained from the experimental data. In this process, several model parameters can be changed. The objective of tuning is to obtain the values of the predicted model parameters to have a closest match with minimal prediction error to the experimentally measured data. In this paper, we have introduced a tuned least absolute deviation (LAD)-based Walficsh/Ikegami (W/I) model using measured UMTS strength data carried out in GRA, Benin City, Nigeria. We found that the performance of the tuned W/I model is the best as root mean square error is lower compared to least square based regression technique. The tuned model with LAD method best fit into BS 2 and BS 3 with an RMSE of 5.41 as compared to least square tuning method which has an average RMSE of 16.68 with BS 2 and BS 3. This successfully validates our tuning methodology and suggests that the tuned model is more accurate for the specified environment.
KEYWORDS: Optimization, Propagation Model Tuning, least absolute deviation nregression method, prediction error, electromagnetic waves, environment.
ABSTRACT
This study presents the effects of gastrointestinal helminth parasites infection on the condition factor (K) of fishes caught from Warri river, over a period 12 months (June, 2010 to May, 2011). Of 800 fishes (belonging to 56 fresh and brackishwater species) examined during the study, 222 (27.5%) were infected with gastrointestinal helminth parasites belonging to three phyla, Platyhelminthes, Nematoda and Acantocephala. The K values of fishes infected with gastrointestinal helminth parasites ranged from 0.03 to 5.05 while that of non-infected fishes ranged between 0.22 and 8.75. The mean K values were not significantly different (P> 0.05). Nevertheless, there was a significant difference in the K value between the sexes for the helminth infected fishes. The males had significantly higher mean condition factor (2.11 + 1.27) than the females (1.78 + 1.16) (P < 0.05). However, for the non-infected fishes, the females recorded a marginal higher mean K value of 1.85 + 1.50, than the males with a mean K value of 1.83 + 1.32 (P>0.05). The mean standard length (SL) of fishes infected with gastrointestinal helminth parasites in the K value range of 1.1–2.0 was significantly higher than that of non-infected fishes (P < 0.05). The results also showed that as the condition factor increased, there was a significant decrease in the standard length of fish.
KEYWORDS: Condition factor, gastrointestinal, helminth parasites, fishes, Warri river.
ABSTRACT
A total of 800 “Nunu” (a fermented fresh milk product) made up of 200 samples each from four major Nigerian cities, namely Abuja, Benin City, Lagos and Onitsha were investigated for the presence and prevalence rate of Enterohaemorrhagic Escherichia coli 0157:H7, using standard microbiological procedures on Sorbitol-MacConkey agar supplanted with cefixime and potassium tellurite (CT-SMCA). All non sorbitol fermenting isolates which were colourless on CT-SMCA, suspected to be Escherichia coli 0157:H7 were characterised serologically using Oxoid Latex agglutination kit and molecularly with PCR techniques. Tissue culture assay to determine the verotoxigenic potentials of all confirmed Escherichia coli 0157:H7 was done on Vero cells. Overall, E. coli was isolated from 268 (33.50%) samples, out of which 51(6.38%) were non sorbitol fermenting E. coli. Non sorbitol fermenters were isolated the most from samples collected in Lagos 17(8.50%) while Benin City recorded the lowest with 7(3.50%). Number of non sorbitol fermenting E. coli isolated from the survey was 31, 16, 58, and 43 from Abuja,
Benin City, Lagos and Onitsha respectively. Of these, 9, 6, 17 and 21 were respectively confirmed as E. coli 0157:H7 with serological characterisation while molecular characterisation with PCR gave a varied result of 7, 5, 13, and 16 respectively. Tissue culture assay on Vero cells confirmed all the E. coli 0157:H7 isolates to be highly verotoxigenic. The findings from this study provide evidence of the presence of E. coli 0157:H7 in our food system as such, health authorities are advised on the need to properly monitor the production and sales of “Nunu” to prevent potential outbreak.
KEYWORDS: Escherichia coli 0157:H7, Verotoxigenic, Nunu, Fermented Milk