Showing papers by "Rivers State University of Science and Technology published in 1996"

Chronic effects of oil spill on soil properties and microflora of a rainforest ecosystem in Nigeria

Abstract: Soil and microbiological properties of a tropical rain forest soil were evaluated 17 years after oil spillage to access the chronic effects of, and interrelationship between population of petroleum hydrocarbon utilizing and nitrifying microorganisms. The spatial distribution of petroleum hydrocarbons (oil), the nutrient status and the abundance of heterotrophic microbes along soil transect lines in the contaminated zones served as the index for corroborating the results. The pH status of soil in the contaminated (Heavy impact — HI, and moderate inpact — MI) zones varied from acidic, that is 4.0 to near neutral PH, that is 6.0. The C content of soils decreased from 3.6% at the HI zones to 2.84% at the MI zones. Total N in the HI and MI zones differed by a factor of 0.10%. Available P was higher at the MI than HI zone, while CEC decreased from a combined mean of 6.48 at the HI zones to 4.46 at the MI zones. Although residual oil content was higher in the HI zones than MI zone, the soil nutrient status within these two zones did not vary significantly (P=0.05). However, soil microbes responded differently. For instance, petroleum hydrocarbon utilizers correlated positively with the distribution of oil in the environment. But, not the nitrifying microorganisms. Aerobic nitrifiers were abundant at the HI than MI zones, while anaerobic nitrifiers were higher at the MI than HI zones. With the presence of petroleum hydrocarbon utilizers anf nitrifying microbes. It is possible to enhance the degradation of oil in the 17 yr old spillage by adopting bioremediation.

Time Course of Biological Nitrogen Fixation, Nitrogen Absorption and Biomass Accumulation in Three Woody Legumes

Abstract: In order to determine how dependent a woody legume can be upon potential N sources, the time course of N2 fixation and N absorption was studied on Gliricidia sepium cv. ILG50, Leucaena leucocephala cv. K28, and Albizia lebbeck in a screenhouse for 16 months using Senna siamea as a reference tree. Dry matter and N yield in all four species increased steadily with time. The numbers and dry weight of nodules also increased with tree age. N-difference and 15N dilution methods correlated well (r = 0.87–0.93) in defining an increasing pattern of N2 fixation with time in all species, with the highest increment rate between sowing and 8 months. The percent N2 fixed ranged from 17.9 to 74%, 27.7 to 71.9% and 43.6 to 83.6%, equivalent to 191 to 3385 mg, 321 to 2863 mg and 533 to 6419 mg N in Leucaena, Gliricidia and Albizia, respectively, for the period between 4 and 16 months. In contrast to others, G. sepium had its peak of amount of N2 fixed at 12 months after planting. In both the proportion and amount...

Screening woody and shrub legumes for growth, nodulation and nitrogen-fixation potential in two contrasting soils

Abstract: In order to identify for alley cropping new candidate species with high biomass and nitrogen-fixing potential, a screening study was conducted on ten woody and shrub legumes (Acacia auriculiformis, Albizia lebbeck, Gliricidia sepium, Leucaena diversifolia, L leucocephala cv K28 and cv K636, Lonchocarpus sericeus, Cajanus cajan, Crotalaria juncea and Tephorsia candida) for 6 months using an acid Ultisol and a non-acid Alfisol A wide interspecific variability of legumes appeared within soil types, and there were significant species-by-soil interactions for many parameters in this study In the acid Ultisol, plant growth in height and grith, nodule numbers, nitrogen yield and N2-fixing potential were significantly (P = 005) lower than those in the Alfisol While Albizia lebbeck was outstanding in both acid and non-acid soil conditions for most performance criteria, L leucocephala cv K28 was most sensitive to soil acidity with 417% of total nitrogen yield in the Ultisol relative to that accumulated in the Alfisol In addition to L leucocephala cv K28 and G sepium, the most common hedgerow species, A lebbeck, L leucocephala cv K636, L diversifolia on Alfisol, and A lebbeck, L leucocephala cv K636, L diversifolia, Tephrosia candida and Cajanus cajan on acid Ultisol, could be considered promising and thus, worthy of further site adaptability trials

N soil exploration and foundations in the recent coastal areas of Nigeria

Abstract: The sub-environnements in the coastal region of Nigeria consisting of meander belt, fresh water and backswamp deposits, mangrove swamps, beach ridge bars and estuaries are underlain by a complex stratigraphical succession of soft silty clay, sand and gravels. The unpredictable stratigraphical succession is complicated by the prevalence of soft and thinly bedded strata which are hardly detected during soil exploration. These thin soft beds introduce inaccuracies on settlement computation and create difficulty in foundation design which frequently lead to unsatisfactory performance. Although some heavy structures can be founded within the sandy formation, occurring on the top layers the stresses induced by such structures can result in indesirable and large total consolidation settlement of the underlying compressible layers. Sensitive structures need therefore be founded on piles, driven to lepths where either sufficient shaft or end-point resistance can be mobilized to ensure satisfactory performance. Strip or raft foundations can easily support structures like bungalows and one storey buildings within the coastal plain sand-and-beach-ridge sub-environments. Ground improvement is generally required in mangrove swamp, meander belt and within the Sombreiro-Warri-deltaic sediments, even for simple structures.

An investigation into public perception and knowledge of science and technology in Nigeria

Abstract: The study examined the perception and knowledge of two hundred and five adults from Port Harcourt metropolis in Rivers State on some issues related to science and technlogy. A questionnaire on public perception and knowledge of science and technology was the main data collecting instrument. Overall findings of the study showed; (1) that some adults are not well informed about science and technology; (2) major differences among respondents on the basis of gender; (3) lack of knowledge by adults on aspects of elementary science. These findings and implications for science and technological literacy were discussed.

Test scores of urban and rural bank workers in Nigeria: an analysis of the effect of location on test performance

Abstract: Reviews the literature relating to job‐related testing, and describes a specific study which examined the test scores, on written tests, of urban and rural bank workers in a national bank. The purpose of the test was to determine the effect of location on test performance of the two sets of bank workers. Also compares the test performance of individual bank workers in both urban and rural branches, and attempts to determine the degree of difficulty and/or ease of the materials to both urban and rural bank workers. Concludes that the location of the bank workers does not have any significant effect on test performance, nor do the individual test scores of both urban and rural bank workers have any significant relationship with location. Also concludes that the test materials were equally difficult for both categories of worker.

Effect of the combined thermal and mass concentration gradients on the stability of a chemically reacting fluid in a porous medium

Abstract: The onset of instability, due to the combined effects of thermal and mass concentration gradients, is investigated in the hydrodynamic stability regime. It is found that the critical Rayleigh number, which determines the onset of instability, increases as the chemical reaction rate constant increases hyperbolically over a wide range of values at both moderate and high permeabilities. In addition, the instability grows with increase in porosity. Previous results show that the critical Rayleigh number rises linearly when only the mass concentration gradient is considered.

Performance of Young Rabbits Fed Graded Levels Dietary Raw Soybean

Abstract: Sese, B.T., Berepubo, N.A. and Ngodigha, E.M. 1996. Performance of young rabbits fed graded levels of dietary raw Soybean. J. Appl. Anim. Res., 9: 89–93. Graded levels (0,5,10,15,20 and 25%) of raw soybean (RSB) were incorporated into six isocaloric and isonitrogenous diets A,B,C,D, E and F, respectively, and fed ad libitum, to forty-eight 6 to 8 weeks old rabbits of the New Zealand white and California strain. Diet A (0% RSB) containing toasted soybean meal served as the control. Feed intake (74.83±7.06 to 79.31±7.55 g/day) and feed efficiency (0.15±0.02 to 0.18±0.03 g gain/g feed) showed no significant difference (P<0.05) among the treatments which resulted in comparable growth rate (11.7±2–17 to 14.0±1.83 g/day) among rabbits on different diets. The dietary incorporation of raw soybean had no significant effect (P<0.05) on percent weight of spleen, kidney, heart, testes and liver. However, RSB inclusion at 25% level led to gross morphological alterations such as inflamation as well as necrosis...

Effect of presensitization of Nocardia asteroides with specific antibody on the viability of the organism.

Abstract: Nocardia asteroides from various growth phases was treated in vitro with normal rabbit sera, immune rabbit sera containing nocardial polyclonal antibodies and a monoclonal antibody. At intervals, samples were grown in broth or on blood agar plates to determine their viability. Log and stationary phase cells were injected intra-peritoneally into female BALB/c mice and their survival rates in the liver and spleen were determined. Presensitization with antibodies reduced the viability of the log phase cells by 48% and that of the late stationary phase by 4%. The antibody-treated log phase organisms were less viable on the blood agar medium and in the spleen and liver than the control organisms. This indicates that pretreatment with antibody has a lethal effect on N. asteroides and affects its survival in vivo.

Elimination of tyramine in protein energy-deficient Wistar rats

Abstract: The in vivo biliary elimination of the dietary amine tyramine was studied in protein energy-deficient rats. Tyramine was administered intraperitoneally at single doses of 1200 μg/kg body weight to Kwashiorkor Wistar rats following cannulation of the bile duct. Excretory products in 24-h samples of feces and urine from both Kwashiorkor and normal cannulated rats, who were similarly dosed with tyramine, were also examined. The feces and urine samples were subjected to spectrophotometric and paper chromatographic analyses that showed the presence of tyramine, p-hydroxyphenylethanol, p-hydroxyphenylacetic acid, p-hydroxyphenaceturic acid, and N-acetyltyramine. Thin-layer chromatography of the bile from test rats followed by ultraviolet analysis of the chromatogram confirmed the presence of unchanged tyramine and the metabolite p-hydroxyphenylethanol. The results confirm that the bile is an excretory route for the amines and also that nutrition plays an important role in the pharmacological or toxic action of ...