On Comparison of Some Imputation Techniques in Multivariate Data Analysis

Listwise or pairwise deletion as the method of handling missing data in multivariate data leads to loss of statistical power, biased results and underestimation of standard errors and P-values.Four imputation techniques namely Regression, Stochastic, Expectation-Maximization (EM) and Multiple Imputation (MI) were considered and compared in terms of preserving the original distribution of the (multivariate) data and the relationships among the variables before the techniques were applied. Results show that none of the techniques performed absolutely better than the rest leaving the choice of imputation techniques in any dataset on the objectives of the researcher. Keyword: Imputation, missing data, Expectation Maximization, Multiple Imputation, Root Mean Square Error

Maximum Likelihood Estimation of the Kumaraswamy Exponential Distribution with Applications

The Kumaraswamy exponential distribution, a generalization of the exponential, is developed as a model for problems in environmental studies, survival analysis and reliability. The estimation of parameters is approached by maximum likelihood and the observed information matrix is derived. The proposed models are applied to three real data sets

Diameter distribution of Nauclea diderrichii (D Wild) Merr. Plantations in a restricted tropical rainforest of Nigeria

Distribution of tree diameter in a specific stand provides basic information for forest management. Little attention is given to the use of probability distribution functions in characterising the stem diameters of most Nigeria indigenous species. This study used Three-parameters lognormal and Weibull probability distribution functions in characterising the diameter of Nauclea diderrichii plantations within a restricted tropical rainforest of Nigeria for sustainable management. Thirty temporary sample plots of dimensions 20 m × 20 m were randomly laid in three age strata (42, 43 and 46 years). Stem diameters of all living Nauclea diderrichii trees with diameter at breast height ≥10.0 cm in all the sampled plots were enumerated. The performance and suitability result revealed that lognormal distribution gave superior description of the stem diameter for the Nauclea diderrichii species in the study area, with least values of Bias (0.00001), Mean absolute error (0.1214), Mean square error (0.7421), Kolmogorov-Smirnov (0.02781) and Anderson Darling (0.49562) statistics. Hence, three-parameter lognormal using maximum likelihood method was recommended for distributing stem diameter of Nauclea diderrichii in the study area.Keywords: Indigenous species; Lognormal; Maximum likelihood; Probability distribution function; Weibul

Challenges of Small Poultry Farms in Layer Production in Ikwuano Local Government Area of Abia State, Nigeria.

The study assessed constraints to increased layers production among small-scale poultry farmers in Ikwuano Local Government Area of Abia State. Data were collected using a multistage sampling technique to select 120 small-scale poultry farmers. Descriptive statistics (frequencies counts, percentages) were used to describe the socio-economic characteristics of the respondents. The result shows that the mean age of the respondents was 48 years and majority (77.5%) of the farmers had higher education. Majority of the respondents (73%) practiced sweeping and packing of dirt in the poultry house as the daily routine management on their farms. The major constraint faced by the respondents was disease and pest attack (76.7%) followed by difficulty in credit and loan procurement processes (73.3%). The study therefore recommends that Government should tackle the problem of loan/credit procurement, market price instability, disease and pest as well as proper funding of small-scale layers poultry business so as to enhance the commercialization of poultry industry in Nigeria.Keywords: Poultry Farms, Layer Production, Socio-Economic Characteristics, Constraints

On Comparison of Exponential and Hyperbolic Exponential Growth Models in Height/Diameter Increment of PINES (Pinus caribaea)

A new tree growth model called the hyperbolic exponential nonlinear growth model is suggested. Its ability in model prediction was compared with the Malthus or exponential growth model an approach which mimicked the natural variability of heights/diameter increment with respect to age and therefore provides more realistic height/diameter predictions as demonstrated by the results of the Kolmogorov Smirnov test and Shapiro-Wilk test. The mean function of top height/Dbh over age using the two models under study predicted closely the observed values of top height/Dbh in the Hyperbolic exponential nonlinear growth models better than the ordinary exponential growth model without violating most of the assumptions about the error term

Comparative Evaluation of Swine Production With Other Domestic Livestock in Mbaitolu Local Government Area of Imo State, Nigeria.

The researcher has undertaken this study on comparative evaluation of swine production with other domestic livestock in Mbaitolu Local Government Council of Imo State, Nigeria to proffer some solution to the problems hindering the rearing of swine in the study areas (Mbieri, Ogwa, Orodo, Ogbaku, Eziama –Obiato, Umunoha, Ifakala, Ubomiri and Afara). The researcher used descriptive survey design to carry out the study. The population for the study was 10,450 respondents drawn from nine towns of Mbaitolu Local Government Council. 600 respondents were proportionally and randomly selected as sample size for the study. General objective was formulated from which five specific objectives were formulated. Among these – is to compare swine prolificacy over the prolificacy of other domestic livestock. Five research questions were formulated to guide this study, among these is – what importance has the prolificacy of swine over other domestic livestocks like goats, sheep, horse and cattle? Five null hypotheses were formulated for the study among these is – there is no significant relationship between the prolificacy of swine over the prolificacy of other domestic livestock in Imo State. Pilot study was conducted at Umuagwo community using 20 respondents that reared domestic livestocks. This area was not part of the study location. Questionnaires were used as a medium for data collection. One sample T-test was used to test five null hypotheses at 0.05 level of significance and all the null hypotheses were rejected meaning that there were significant differences between pig productions over the production of other domestic livestock. The analysis yielded the following results: swine production was accepted to be more prolific than other domestic livestocks like goats, sheep, horse and cattle. It was also agreed that swine were more adapted to wide varieties of feeds which made them to grow more quickly than other domestic livestocks. It was concluded that swine production was more economically important than the rearing of other domestic livestock. It was recommended that National Poverty Eradication Programme (NAPEP) in Imo State should enlighten the respondents on the economic importance of swine production over the rearing of other domestic livestock. Piglets should be made available to farmers who wish to embark on swine production at affordable price by Anambra – Imo  River Basin Development Authority (AMRBDA).Keywords: Swine Production, Domestic Livestock, Mbaitolu Local Government Council

Moringa oleifera Lam extract attenuates gastric ulcerations in high salt loaded rats

Moringa oleifera Lam is a plant used extensively both in traditional and orthodox medicine to treat myriad ailments, including gastrointestinal disorders. This study was carried out to investigate the effect of leaf extract of M. oleifera some gastrointestinal function parameters in high salt loaded rats. Acute toxicity study was done using 70 male white mice (18-20 g) were used for the study. They were randomly selected and assigned to 7 cages of 10 animals per cage. Percentage mortalities were converted to probits and plotted against the log10 of the dose of the extract from which the LD50 value was calculated. Fresh leaf extract of M. oleifera was Soxhlet extracted. 24 albino Wistar rats were randomly assigned into 4 main groups of 6 rats each. Fed on normal rat chow, high salt (8% NaCl) diet + 1% NaCl drinking water and/or M. oleifera extract (600 mg/kg bw). The feeding regimens lasted for 42 days. Results obtained revealed that the extract had an LD50 value of 1,872.22 mg/kg from which a test dose of 600 mg/kg was derived for the feeding regimen. The salt fed rats had significantly (p<005) raised basal gastric acid output (9.03 ± 0.17 mmol/L/hr) compared with control (7.27 ± 0.17 mmol/L/hr), but had blunted response to administered histamine and cimetidine, while treatment with the extract enhanced the sensitivity of histamine in high salt loaded rats. Gastric mucus concentration was significantly (p<0.05) higher in the salt untreated group (0.25 ± 0.004 g) compared with other groups. The salt fed untreated group also had significantly (p<0.05) raised gastric ulcers (10.83 ± 0.70) compared with other groups, these were reversed following Moringa treatment. In conclusion, Moringa oleifera extract reverses gastric ulcers and blunted histaminergic receptors in high salt fed rats. The mechanism by which high salt increases gastric secretion is independent of the histaminergic mechanism

Design, Development and Testing of a Neem Seed Steam Roaster

A neem seed roaster which makes use of steam as source of heat energy was designed and fabricated to be used in heating neem seeds prior to expelling oil from them. It helps to check the disadvantage of using seed scorchers which produces burnt or unevenly heated seeds which results in black oil formation. The equipment consists of an insulated heating unit, roaster, seed inlet unit, seed discharge outlet, power transmission unit and the frame work. A gear motor of 0.25kW was selected to supply power to the shaft whose end was welded to the stirrer. The roasting unit consists of three compartments: roasting chamber, steam chamber and insulator chamber. The insulated heating unit has two pipes: water inlet pipe and steam delivery pipe. Also, two electric heating elements of 2.75kW each were installed in the heating unit to help boil the water for steam to form; this steam will then be transported by the steam delivery pipe to the steam chamber which in turn heats up the outer surface of the roasting chamber and thus the seeds inside are roasted through the heat being supplied. The machine was fabricated with about 90% local materials. Test results of the seed roaster using neem seeds indicate successful heating/roasting, the seeds were not scorched or burnt, rather they were looking dry but fresh, this indicates that the design of the machine suits its purpose for heating neem seeds prior to oil expelling . The machine being a simple one will be easy to maintain by the local artisans. Keywords: Heating, steam, neem seed, roaster, desig

Bacterial Indicators of Contamination in Highly Impacted Segment of Tropical Lagoon, Southwest Nigeria

Increasing deterioration of coastal waters is a major public health concern in many regions of the developing world. This study investigates the impact of water quality on the proliferation of bacterial pathogens in surface water, sediment and tissues of fish, Sarotherodon melanotheron from the Makoko axis of Lagos Lagoon. Analysis of physicochemical characteristics and microbial quality of samples followed standard methods and procedures.&nbsp; Measured water quality parameters (water temperature, turbidity, pH, salinity and dissolved oxygen) which showed no significant variation (p&gt;0.05) across study stations were within the Nigerian Federal Environmental Protection Agency set limit The highest total bacterial count (TBC) (214.09±43.95 x 105 CFU g-1), total coliform counts (TCC) (91.15±15.05 ×104 CFU g-1) and total faecal coliform (TFC) (36.22±12.98×10³ CFU g-1) were recorded in fish muscle tissue while the lowest TBC (52.39±39.72 x 105 CFU ml-1), TCC (33.45±33.94 ×104 CFU ml-1) and TFC (0.19±0.18×10³ CFU ml-1) were recorded in water sample. The bacterial species with the highest percentages of occurrence in water, sediment, fish gill and fish muscle tissue were Klebsiella pneumoniae (22.11 %), Enterobacter aerogenes (32.37 %), Escherichia coli (32.97 %) and E. coli (29.00 %) respectively. A very strong positive correlation (r = 1.00) was obtained between TBC in water and salinity as well as with dissolved oxygen levels. Likewise, the TBCs in fish parts (muscle tissue and gill) were positively correlated with the water temperature and turbidity. On the other hand, a negative correlation was obtained between pH and TBC in fish muscle tissue (r = -0.81) as well as with fish gut (r = -0.77). The relatively high counts of pathogenic bacteria species recorded during the study have serious public health implications

Comparative Study on Linear and Non-Linear Geostatistical Methods: A Case Study on Kalsaka Hill Gold Deposit, Burkina Faso

Selecting an appropriate method to evaluate an ore deposit is imperative in resource estimation since it becomes the basis for reliable planning and development of a mine. Even though linear geostatistical methods such as Ordinary Kriging (OK) give reasonable estimates, there may be instances where recoverable resource estimates are difficult to obtain, particularly when the deposit is characterised by a positively skewed grade distribution with some outliers. Multiple Indicator Kriging (MIK), which is a non-linear estimation technique, is not based on any assumption about the distribution underlying the data and offers realistic solutions to problems associated with skewness and outliers. This paper looks at the use of MIK technique as an alternative method of recoverable resource estimation to OK by comparing the resource estimates obtained from MIK and OK models. OK model showed more smoothing effect on its estimates than the MIK model as evidenced in swath plots. Underestimated grades and tonnages were observed when OK was used to estimate a gold deposit at Kalsaka, according to the grade and tonnage reconciliation. MIK model yields estimates which are higher and closer to the actual than the OK model estimates. Keywords: Gold, Multiple Indicator Kriging, Ordinary Kriging, Outlier, Variograph