Occupational mobility in engineering profession (craftman and artisan) in Oyo State, Nigeria.

This paper evaluate occupational mobility in engineering professional in Oyo State of Nigeria with the goal assessing causes and readiness of the professionals to return to the profession when the hindering factors are removed as well as sufficiency of the survey instrument in addressing the research problems. The study was conducted using a well structured questionnaire administered in 20 local government of Oyo State, Nigeria representing the sample space of 0.424. The Cronbach’s alpha of the reliability test of 0.453 was returned for the scale mean statistics of 11516.83 and variance of 0.0000007 showing that the survey instrument was sufficient and could be relied upon. The result of the socio economic analysis showed that 80% of the respondents were married while (15%) were single and the rest (5%) were divorced. The age distribution of the respondents ranged between greater than 50 years groups (12%) and 30 -39 years group (39%).The result of the analysis of job characteristics of the respondents showed that the longer the year of graduation, the lesser the number of graduates still in the business. The cross table analysis of the socio-economic indices with the job status of the respondents showed that marital status and level of education does not have significant effects on the job status of the respondents (whether still practicing or not) because 1.454 and 5.223 returned for both marital status and level of education are not significant (P<0.05). Also, the contingency table analysis of the effects of the skill acquisition methods showed that more of the respondents who acquired their skill via Technical School (70%) are willing to go back to the professions. However, for those who acquired their skill through Learning/artisanship, less than average (32%) of the respondents are ready to return to the profession. Lastly, the establishment of the regression model for the relationship between the proportion of the people wishing to go back to the profession and year of practicing the profession provide a necessary impetus for addressing the Job mobility problem faced by the profession

Cement Stabilized Structural Foundation Lateritic Soil with Bone Ash Powder as Additive

Investigation on the potentials of bone ash powder on cement stabilized structural foundation was carried out in this paper. The aim of the study was to discover local waste material as complement for cement to reduce construction cost. Three soil samples were collected from different borrow pits in Ile-Ife and Ibadan, Nigeria called sample A, B and C. Preliminary tests such as the natural moisture content, specific gravity, grain size analysis and Atterberg’s limits were performed on the samples at their natural states and when stabilized at the condition of 8, 8 and 6% cement for samples A, B and C respectively. Engineering tests such as compaction, California bearing ratio (CBR) and undrained traixial were also performed on them at their natural states, when stabilized with optimum cement and when bone ash powder (BAP) was introduced at 2, 4, 6 and 8% to the samples. The results of the engineering tests showed that BAP increased the maximum dry density (MDD) of all the samples. With the optimum cement content kept at 8% for samples A and B and 6% for sample C, the values increased from 1687.89 to 2219.05 kg/m3&nbsp;and 1634.12 to 2174.71 kg/m3&nbsp;at 4% in samples A and B respectively and 1521.59 to 1620.70 kg/m3&nbsp;in sample C at 2% BAP content. The unsoaked CBR values of all the cement stabilized samples dropped with BAP contents. The values dropped from 4.79 to 1.79%, 3.88 to 2.31% and 4.84 to 2.43% respectively in samples A, B and C. However, the shear strengths of samples A and B increased from 604.77 to 740.09 kN/m2&nbsp;and 317.73 to 616.05 kN/m2&nbsp;respectively. It was therefore concluded that BAP is not an effective additive on cement stabilized structural foundation soil, except in the compaction and shear strength characteristics

Appraisal of the national biosafety management agency (NBMA) Act 2015

Since the advent and subsequent advancements in the field of biotechnology, there have been diverse reactions from stakeholders and experts in this rapidly growing field as to the advantages and adverse effects of products from biotechnology on the consumers, economy and the ecosystem as a whole. In the Nigerian context, this article examines the National Biosafety Management Agency Act 2015 in a bid to determine its adequacy or otherwise in regulating Genetically Modified Organisms (GMOs) and biotechnology generally, knowing fully well that technology keeps advancing and laws should be drafted in such a way as to accommodate scientific developments and advancements.Keywords: National Biosafety Management Agency Act 2015, Technology, Law, Nigeri

Minimizing Interference in Ultra-Dense Femtocell Networks Using Graph-Based Frequency Reuse Technique

This paper investigates the performance of graph colouring schemes for frequency assignment in Long-Term Evolution (LTE) networks with ultra-dense femtocells. The aim of the study is to minimize interference in such networks while ensuring efficient spectrum use for these femtocells. The three schemes investigated are the conventional greedy graph colouring algorithm, the saturation degree algorithm and our proposed graph-based theory (GBT) algorithm. The process of frequency assignment is similar in the last two except that the proposed GBT partitions the femtocells into independent sets for an efficient frequency re-use. The performance of these three schemes was analyzed through extensive simulations to determine the SINR and network capacity that can be obtained with the deployment of these schemes using the ITU-R P1238-7 path loss model. The outcome of this study showed that with the absence of a dynamic frequency assignment scheme, interference level is increased as the number of femtocell users within a particular coverage is increased, leading to a reduction in the capacity of such networks. Simulation results showed that all three algorithms considered have the ability to allocate frequencies to femtocells and minimize interference in a densely deployed environment, thereby increasing network capacity. The proposed GBT assigned the least sub-band thereby ensuring spectral efficiency while minimizing harmful interference. Results show that the greedy algorithm has a disadvantage of inefficiently assigning sub-bands randomly, while the saturation degree assigns more sub-bands when compared with the GBT scheme.Keywords — Femtocell, graph colouring, frequency assignment, LTE

A Comparative Study of Biosurfactant Synthesis by Pseudomonas aeruginosa Isolated from Clinical and Environmental Samples

Evaluation of emulsifying activities indicates that biosurfactants were produced by an environmental (strain EP1) and a clinical (strain CP1) species of Pseudomonas aeruginosa. During growth on hydrocarbons, the organisms produced biosurfactants. Both strains grew luxuriantly on motor oil and readily synthesized abundant surfactants at the expense of easily metabolizable substrates. During a 12-day cultivation on motor oil, the organisms produced growth-associated extracellular surfactants with emulsification activities of 71 and 38% for EP1 and CP1, respectively. The generation times obtained for EP1 and CP1 were 1.74 and 2.66 days. The biosurfactants that could not be secreted on glucose were partially purified and putatively identified as rhamnolipids. The surface-active compounds present high emulsification activity and stability in the pH range of 3.0–10.0, temperature range of 4°C–100°C, and salinity range of 16–44% and are capable of stabilizing oil-in-water emulsions with several hydrocarbons. Typical emulsions produced were stable for several weeks. The results also showed that the biosurfactants were able to remove a significant amount of crude oil from contaminated soil; for instance, strain EP1 surfactant removed 54%, CP1 41%, detergent 42%, and water 30%. The rhamnolipids from these strains represent a new class of biosurfactants that have potential for use in a variety of biotechnological and industrial applications where extremes of pH, thermal, and saline conditions would have little or no effect on activity

Observation for spoilage in fish and beef in a daily simulated local market style of Southwestern, Nigeria

The degree of spoilage of fish and beef in a daily simulated market style of southwest, Nigeria was determined by Trimethylamine (TMA) levels in each sample using the standard pictrate technique. 100g of each of the three different parts of a bull (liver, meaty and fatty tissues) and fresh African cat fish (Clarias gariepinus) (liver, meaty portion and head) were purchased twice a week for five weeks from the abattoir and Oja-Oba market in Akure respectively. The samples were subjected to ambient temperature and their degree of spoilage was assessed after 3 hours, 6 hours and 9 hours of purchase. The results showed that, there was no significant difference (P≥ 0.05) in the effect of time (hours) on TMA concentration in different parts of the fish and bull samples, though, the mean concentration of TMA in the fish samples increased with time. However, the degree of spoilage is slower in the bull compared to the fish samples but higher in the late evening (9 hours). Hence, buying and selling of beef in the late evening should be discouraged to avoid consumption of unwholesome meat with high TMA concentrations, while fish should be stored-frozen and sold in deep freezers

Toxicity evaluation of waste effluent from cassava-processing factory in lagos state, nigeria using the Allium cepa assay

Mutagenic and genotoxic effects of cassava wastewater (CWW) were investigated by assay of Allium cepa root meristematic cells. The physicochemical parameters of the wastewater samples showing cyanide content were also determined. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the CWW and distilled water was used as a negative control. After 72 h, the root tips from the treated bulb were processed for cytological studies by orcein squash technique. The mean lengths of root bundles were obtained and effective concentration (EC) values calculated. The cytotoxic effects on the onion root tips showed strong growth retardation at high concentrations of the effluent with EC value of 10%. The 50 mitotic index (MI) rapidly decreased with increasing effluent concentration compared to control. There was significant increase in frequency of chromosome aberrations (sticky chromosome, c-mitosis, vagrant chromosome, bridges fragment, binucleated cells, multipolar anaphase, attached chromosome and laggard chromosome) in root tip meristem cells of Allium cepa at all tested concentrations. Further analysis using oneway ANOVA revealed that there was a statistically significant difference (p<0.05) in concentration-dependent inhibition of onion root growth, mitotic index and induction of chromosomal aberration in the Allium cepa test. The results indicate that the effluent samples collected were highly mutagenic. The results of physicochemical analysis revealed that the concentrations of some parameters (conductivity, total suspended solid (TSS), total dissolved solid (TDS), biological oxygen demand (BOD), nitrate, cyanide, chloride and metals-magnesium, aluminum, chromium, cadmium, manganese and iron) were above the maximum permissible limit set by world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The findings indicate that the substances contained in the cassava effluents may be toxic to living organisms and may pollute the environment if untreated

Genotoxicity Evaluation of Landfill Solid Waste Leachates from a Waste Dumpsite in Lagos State, Nigeria using the Allium cepa Assay

The management of municipal landfill’s leachate is considered one of the most significant environmental issues. Potential mutagenic and genotoxic effects of solid waste leachates (SWL) were investigated using the Allium cepa root meristematic cells assay technique. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the SWL and distilled water was used as a negative control. The root tips from the treated bulb were processedby orcein squash technique after 72 h. The mean lengths of root bundles were obtained andeffective concentration (EC) values calculated. Some of the physicochemical properties of the WL were also determined. The A. cepa assay was carried out at concentrations of 0.05, 0.1, 2.0, 5, 10, 20, 50 and 100% of the WL. There was a statistically different (p < 0.05), concentrationdependent inhibition of onion root growth and mitotic index, and induction of chromosomal aberrations in the onion test. The results of the physicochemical analysis revealed that the concentrations of some parameters were above the maximum permissible limit set by the world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The landfill leachates pose a risk to human health and the environment in general. Hence, ecotoxicity/genotoxicity assays would be useful in leachate risk assessment when coupled with physicochemical analysis