Rainfall-Runoff Relationships and flow forecasting, Ogun river Nigeria

An excess or a lack of rainfall are the major causes of most hydrological hazards, and the need for a systematic approach to river flow forecasting based on rainfall is imperative, especially in Nigeria. A study was carried out on three major gauging stations of the Ogun river basin to determine the rainfall-discharge relationship and model equations for use in the basin and similar basins. Stream flow and rainfall data for at least seven consecutive years for each station were collected and analyzed. The rainfall-runoff data were subjected to linear, exponential and higher order analysis. Stream flow data were also fitted to normal, log-normal and log-Pearson Type III distributions. The selection of the appropriate probability distribution model for each gauging station was based on graphical comparisons between observed and predicted flows and goodness-of-fit tests using chi-square and probability correlation coefficients. Results show that model equations with logarithmic and exponential relationships between rainfall and discharge gave better and more realistic prediction estimates and can be used for the basin. It was determined that the peak discharges occurred when the rainfall values were at their maximum, and a distinct relationship between the discharge and rainfall exists at each of the gauging stations

Growth response of Heterobranchus longifilis fingerlings fed with varying levels of dietary freshwater mussel (Aspatharia sinuata)

A common bivalve: Freshwater mussel, Aspatharia sinuate was evaluated as a dietary protein supplement in the production diet for Heterobranchus longifilis fingerlings with mean body weight 8.34 plus or minus 10g reared in aquaria tanks. Four diets containing fishmeal protein at a rate of 25%, 50% and 75% along with the freshwater mussel flesh were formulated. The diet without the freshwater mussel served as the control. The fish fingerlings were fed at 5% body weight per day for 56 days. It was revealed at the end of the experiment that freshwater mussel was most suitable as a protein supplement when incorporated at 25% replacement. The body weight gain, specific growth rate and feed conversion ration values of 6.83g, 1.06% day and 0.62 respectively were highest in diet with 25% replacement closely followed by diet with 50% replacement. Beyond 75% inclusion level there was no significant growth (P>0.05). However, complete replacement of fishmeal by freshwater mussel decreases growth rates and should not be used in Heterobranchus longifilis diet

ASSESSMENT OF RADIONUCLIDES IN SOME NIGERIAN MADE CEREALS AND TEA PRODUCTS

This study investigated the presence of the radionuclides 226Ra, 232Th, 40K and 137Cs in some cereals and tea products commonly available in Nigerian markets. Fifteen cereal samples and ten tea samples were purchased from different markets in Lagos, Nigeria. Gamma-ray spectrometric analyses of the samples were done using a High Purity Germanium (HPGe) detector to obtain the activity concentrations of the radionuclides with 137Cs being below the detection limit in all the samples analyzed. The mean activity concentrations (in Bqkg-1) of 226Ra, 232Th and 40K in the cereal samples were (0.839 ± 0.713), (1.153 ± 1.084) and (22.514 ± 8.897) respectively; while the values for the tea samples were (1.145 ± 0.765), (0.94 ± 0.601) and (19.212 ± 9.533) respectively. The associated hazard indices for the cereals ranged from 0.0065 to 0.0368 while that for the tea products varied from 0.0044 to 0.0292. These values are well below the world recommended limit of 1.0. The calculated annual effective doses due to the ingestion of the investigated samples ranged from 0.068 mSvy-1 (for age groups from 1 y) to 0.189 mSvy-1 (for age group 17 y). For the tea samples, the highest value was found in the age group 12 – 17 y, while the lowest was found in the age group 1 – 2 y. These values are below the allowable level of 1 mSv per annum for members of the general public as recommended by the International Commission on Radiological Protection. This indicates that the consumption of these cereals and teas do not pose as health hazards to both children and adults in the populace.   &nbsp

Growth and survival of different sex combinations of Oreochromis niloticus (L) in glass tanks

Growth performance and survival rates of three different sexes of Oreochromis niloticus fingerlings (27.5~c 0.02g); mixed-sex, all male and all female fed 35% CP at 5% body weight was carried out for 56 days in indoor rearing operations. Aquaria tanks (60x30x 30cm3) were used as rearing tanks and each treatment was replicated. All female tilapia had the best specific growth rate (2.54%/day), food conversion ratio (1.98) as well as survival rate (98%), least value was obtained in treatment containing the mixed sex tilapia. Specific growth rate (2.06%/day), Food conversion ratio (2.27) and survival rate (95% )

STATISTICAL ANALYSIS OF TEMPORAL VARIATIONS IN INDOOR RADON DATA USING AN ADAPTED RESPONSE SURFACE METHOD

Temporary variations in indoor radon data (IRD), comprising radon concentration (RC), air temperature, relative humidity and barometric pressure were monitored hourly over a period of two months in a bungalow house in Abeokuta, Nigeria. A total of 1510 data was assembled and analyzed statistically using Shapiro-Wilk for normality test, response surface method (RSM) and adapted response surface method (ARSM) to investigate and model the influence of the meteorological parameters on the variations of RC in indoor air. The overall results showed that RC varies widely over time and correlates positively with relative humidity and temperature, but negatively with barometric pressure. Specific results of the two response surface methods were compared and contrasted and the multiple linear regression model of the ARSM was highlighted and established as the appropriate method for analyzing IRD. ARSM was presented in an easily reusable form that can easily be adopted by researchers and data analysts.ª¤

Evaluation of different soybean-based diets on growth and nutrient utilization of Heterobranchus longifilis in aquaria tanks

In order to compare the effect of raw, cooked, toasted and extruded soybean meals on the growth and nutrient utilization of Heterobranchus longifilis fingerlings, 120 pure Heterobranchus longifilis fingerlings were purchased at the National Institute for Freshwater Fisheries Research (NIFFR) improved genetic fish hatchery and randomly allocated into four different treatments with two replicates each with 15 fingerlings in 8 aquaria tanks. Four different diets containing 40% crude protein each were compounded and fed to the fish at 5% body weight for 56 days. At the end of the feeding trials, growth performance and nutrient utilization were evaluated. The results revealed that fish fed toasted soybean-based diets had highest mean weight gain (MWG) of 16.39g, specific growth rate (SGR) of 2.03%/day, and food conversion ratio (FCR) of 2.18. The fingerlings fed the extruded soybean-based diet gave the least growth performance. It could be concluded in practice, that toasted soybean-based diet is optimal for growth of Heterobranchus longifilis fingerlings

Declining prevalence of duodenal ulcer at endoscopy in Ile-Ife, Nigeria

Background. Duodenal ulcer is the most common peptic ulcer disease worldwide. In the past, sub-Saharan Africa has been described as an area of mixed prevalence for peptic ulcer disease, but recent reports have disputed this. Changes in the prevalence of duodenal ulcer have been reported, with various reasons given for these.Objective. To describe the change in endoscopic prevalence of duodenal ulcer at Obafemi Awolowo University Teaching Hospital (OAUTH), Ile-Ife, Nigeria, between January 2000 and December 2010.Methods. This was a retrospective, descriptive study of patients who underwent upper gastrointestinal endoscopy in the endoscopy unit of OAUTH between January 2000 and December 2010. The data were obtained from the endoscopy register, demographic indices, presenting symptoms and post-endoscopic diagnoses being retrieved for each patient. The study period was divided into the years 2000 - 2004 and 2005 - 2010, the frequencies of duodenal ulcer and other post-endoscopic diagnoses being compared between these two time periods to see whether there were changes.Results. Over the study period, 292 patients (15.8%) were diagnosed with duodenal ulcer, second only to 471 patients (26.2%) with acute gastritis. The prevalence of duodenal ulcer for 2000 - 2004 was 22.9% (n=211 patients) compared with 9.2% (n=81) for 2005 - 2010 (p<0.001).Conclusion. There was a significant decline in the endoscopic prevalence of duodenal ulcer over the decade

Wound Complications Following Laparoscopic Surgery in a Nigerian Hospital

Background: Different complications may occur at laparoscopic port sites. The incidence of these varies with the size of the ports and the types of procedure performed through them. Objectives: The aim was to observe the rate and types of complications attending laparoscopic port wounds and to identify risk factors for their occurrence. Patients and Methods: This is a prospective descriptive study of all patients who had laparoscopic operations in one general surgery unit of a University Teaching Hospital in Nigeria between January 2009 and December 2012. Results: A total of 236 (155 female and 81 male) patients were included. The laparoscopic procedures include 63 cholecystectomies, 49 appendectomies, 62 diagnostic, biopsy and staging procedures, 22 adhesiolyses, six colonic surgeries, eight hernia repairs and 22 others. Port site complications occurred in 18 (2.8%) ports on 16 (6.8%) patients including port site infections in 12 (5.1%) and hypertrophic scars in 4 (1.7%) patients, while one patient each had port site bleeding and port site metastasis. Nine of 11 infections were superficial, while eight involved the umbilical port wound. Conclusion: Port site complications are few following laparoscopic surgeries in our setting. We advocate increased adoption of laparoscopic surgeries in Nigeria to reduce wound complications that commonly follow conventional open surgeries.Keywords: Laparoscopy, Nigeria, wound complication

Electro-thermo-mechanical modelling and analysis of the Press Pack Diode in Power Electronics

This paper details a finite element modelling approach of the press pack assembly process for a diode in a power electronic module. Molybdenum and aluminum graphite have been investigated as suitable materials for the contact pad. Contact analysis has been used to model the pressurized thermal interface in order to extract both the stress and temperature distribution in the diode. Average temperature and von Mises stress on the chip for a combination of clamping pressure, load current and contact pad material have been extracted from the modeling results. At present, based on the assumptions and modeling parameters used, Aluminum Graphite seems to have better performance in comparison with molybdenum in terms of generating a lower average chip temperature. Additionally optimum clamping pressure has been estimated by performing a numerical optimisation analysis in order to minimise both the average temperature and stress in the chip

Polyp prevalence at colonoscopy among Nigerians: A prospective observational study

Background: This study was aimed at identifying the prevalence, distribution, and clinicopathologic characteristic of colonic polyps among Nigerians undergoing colonoscopy at the Obafemi Awolowo University Teaching Hospitals complex, Ile‑Ife, Nigeria. We also determined the polyp detection rate (PDR), polyps per colonoscopy (PPC) and adenoma detection rate (ADR).Materials and Methods: This is a prospective study of all colonoscopy examinations performed at the endoscopy unit of our hospital from January, 2007 to December 2013. The patient demographics, indications for colonoscopy, colonoscopic findings, number of the polyps, their sizes, possible risk factors in the individual case histories, and histopathological characteristics of the polyps.Results: During the study period, a total of 415 patients met the inclusion criteria and only 67 out of these had colonic polyps. The overall PDR was 16.1%. The age ranged was 2‑87 years with a median of 57 years. Forty‑three (64.2%) patients were 50 years or above and there were 40 (59.7%) males. Thirty‑three (49.3%) patients were referred as a result of lower gastrointestinal bleeding, 14 (20.9%) for colorectal cancer (CRC) and 13 (19.4%) for routine screening. Thirty‑nine (58.2%) patients had the polyps at the rectosigmoid region of the colon, 17 (25.4%) had the polyps located proximal to sigmoid colon and 11 (16.4%) patients had multiple polyps involving both segments. Adenomatous polyps was the most common (28 [47.5%]) histopathological finding of which two patients had adenomatous polyposis. Other findings include inflammatory polyps in 17 (18.8%) patients, 5 (8.5%) patients each had hyperplastic and malignant polyps, while 4 (6.8%) patients had juvenile polyps. The ADR was 6.8 and the PPC was 0.2. Statistically, patients 50 years and older were more likely to have adenomatous and hyperplastic polyps than those younger than this age (P = 0.010).Conclusion: We conclude that polyps are probably not as rare among black Africans especially when they are above 50 years. Our histopathological finding of adenomatous change in a good proportion of the detected polyps show that they are likely to be associated with CRCs in our compatriots and as such we would recommend a routine screening colonoscopy for Nigerians aged 50 and above.Key words: Adenoma, hyperplastic, inflammatory, Nigeria, polyps, prevalenc