Estimation of contaminant transport parameters for a tropical sand in a sand tank model

This research describes the goals, design and implementation of a quasi natural gradient, laboratory scale, sand tank (aquifer) model experiment. The model was used to study the transport of an inorganic tracer (Chloride) in groundwater, within a tropical aquifer (porous medium) material. Three-dimensional sand tank (1.8 m × 0.3 m × 0.8 m) experiments were conducted to investigate contaminant transport and natural attenuation within the sand tank. In all, 360 samples were collected during 24 sampling sessions, for the three days of the tracer experiments in the Sand Tank. The Owena sand is a poorly graded sand with 88.1 % sand and 11.9 % gravel. Geotechnical properties including; coefficient of uniformity Cu = 2.53, coefficient of gradation Cz = 0.181, hydraulic conductivity K = 5.76 x 10-4 m/s, bulk density ρ = 1.9 Mg/m3, effective porosity ne = 0.215 and median grain diameter D50 = 0.55 mm, were determined. Other relevant hydraulic and solute transport parameters, such as dispersion coefficients and dispersivities were also established for the tropical soil

Primary postpartum haemorrhage in Lagos, Nigeria

No Abstract

HISTOLOGICAL AND HISTOCHEMICAL OBSERVATIONS ON THE REPRODUCTIVE ORGANS OF Archachatina marginata ovum (GASTROPODA: ACHATINIDAE) AT DIFFERENT REPRODUCTIVE STATES

The histological and histochemical variation in association with morphological variation in the repro-ductive system of Archachatina marginata ovum was the target of this investigation. Forty- five snails were dissected and categorized into 5 different reproductive stages (low mating, high mating, high egg, gravid and post reproductive). The reproductive tracts which include: hermaphroditic duct, albu-men gland, spermoviduct and spermatheca and the ovotestis were processed for histological and histochemical staining. There were some variations in the architecture of the reproductive organs be-tween the active (high mating, high egg and gravid) and non active stages (low mating and post repro-ductive) states. The active states were generally associated with colloidal or granular secretions. Gly-cogen and alkaline phosphatase activities were associated together throughout the epithelium of the reproductive system of A. marginata ovum and they were more strongly indicated in tissues that are intimately connected to the growth and development of gametes. It was concluded that morphological variation in the secreting glands of the reproductive system of A. marginata ovum is closely associated with changes in the functional secretory activities of the glands

MORPHOMETRIC STUDY OF THE REPRODUCTIVE SYSTEM OF GIANT AFRICAN LAND SNAIL Archachatina marginata ovum (Pfeiffer) (Pulmonata: Achatinidae) FOUND IN ILE-IFE, SOUTHWESTERN NIGERIA.

The morphometry of the reproductive organs of the giant African land snail, Archachatina marginata ovum from wild collection at Ile-Ife, southwest Nigeria, was assessed during March - May (early rainy season) and August – October (late rainy season) of 2010. A total 134 snails were dissected and clas-sified into one of five different reproductive states (low mating readiness; high mating readiness; egg production; gravid and post reproductive). The five states were observed in snails collected during the early rainy season, whereas the gravid state was not observed in the collections during late rainy sea-son. Albumen gland was considerably enlarged at egg production state forming about 60 % of the total weight of the reproductive system, while vas deferens was significantly longer in snails at high mating readiness state. The sizes of the reproductive organs were not substantially related to the size of the snail as the coefficient of determination (r2) of the relationship were in most cases below 0.5. The over-all results indicated that variations in the morphology of the reproductive organs of A. marginata ovum are mostly state dependent and less related to the size of the snail and thus could be used reliably to categorise the snails into reproductive states

Assessment of frequency, density and abundance of weed species in different Cropping Systems

This study was conducted at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria to determine effect of cropping systems on weed diversity  and weed seeds bank at various soil depths. Weed flora composition in different cropping systems were also correlated with land use history. Two broad  cropping systems were considered namely; plantation cropping (cocoa, oil palm and cashew) and arable fields (maize, cassava/maize and a natural fallow which served as control. Twenty six weed families were recorded in all. Out of these 26 families, only two are grasses while the remaining were broadleaves. Oil palm and cashew plantations had the highest weed diversity. Using Shannon index (H>1.0), Panicum maximum (Poaceae) and Vigna gracilis (Papilionaceae) weeds were more frequently encountered across the cropping systems with diversity index H>0.5. Asteraceae, Papilionaceae, Rubiaceae were the broadleaves families widely distributed in the cropping systems. Results on the weed seed bank indicated that the number of weed seeds decreased as soil depth increased, the highest number of seeds was found in the soil layer of 0-8 cm. Keywords: Cropping System, Seed bank, abundance, densit

The study assessed the health risks associated with street trading activities among selected mothers in urban centers of Nigeria. The data used was extracted from national survey data among 3,873 street traders selected in various Central Business Districts (CBDs) across three major cities of Nigeria, namely, Lagos, Kano and Port Harcourt. The study showed that street trading has provided job opportunities for mothers but the impact of the business on their welfare is not visible considering their weekly income that is far below their weekly expenditure. Respondents with primary, secondary and tertiary education are 0.879, 0.553 and 0.818 less likely to be injured while trading on the street compared to individuals who have no formal education. The authors suggest due recognition to be given to the activity and that street traders-government partnership be established in order to safeguard the health of the operators.

The study assessed the health risks associated with street trading activities among selected mothers in urban centers of Nigeria. The data used was extracted from national survey data among 3,873 street traders selected in various Central Business Districts (CBDs) across three major cities of Nigeria, namely, Lagos, Kano and Port Harcourt. The study showed that street trading has provided job opportunities for mothers but the impact of the business on their welfare is not visible considering their weekly income that is far below their weekly expenditure. Respondents with primary, secondary and tertiary education are 0.879, 0.553 and 0.818 less likely to be injured while trading on the street compared to individuals who have no formal education. The authors suggest due recognition to be given to the activity and that street traders-government partnership be established in order to safeguard the health of the operators

Background radiation dose of dumpsites in Ota and Environs

In-situ measurement of background radiation dose from selected dumpsites in Ota and its environs was done using Radialert Nuclear Radiation Monitor (Digilert 200). Ten measurements were taken from each dumpsite. The measured background radiation range between 0.015 mRhr-1 for AOD and 0.028 mRhr-1 for SUS dumpsites. The calculated annual equivalent doses vary between 1.31 mSvyr-1 for AOD and 2.28 mSv/yr for SUS dumpsites. The air absorbed dose calculated ranged from 150 nGyhr-1 to 280 nGy/hr for AOD and SUS dumpsites respectively with an average value of 217 nGyhr-1 for all the locations. All the estimated parameters were higher than permissible limit set for background radiation for the general public. Conclusively, the associated challenge and radiation burden posed by the wastes on the studied locations and scavengers is high. Therefore, there is need by the regulatory authorities to look into the way and how waste can be properly managed so as to alleviate the effects on the populace leaving and working in the dumpsites vicinity

Effect of Weed Control Methods and Canopy Characteristics on Weed Biomass, Yield and Yield Components of Two Contrasting Cassava Varieties in the Rainforest Zone of Nigeria

Weed infestation is one of the reasons why the average cassava yield is low in Nigeria. This study was conducted in 2010 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife to evaluate the impact of different cassava canopy structures on (i) weed biomass and (ii) yield and its components. The treatments consist of hand-weeded, herbicidal treatment, and unweeded checks in the main plot. The sub-plots constituted the cassava cultivars (TMS 30572 and TME 1) laid out in a randomized complete block with a split-plot arrangement in three replications. TMS 30572 reduced weed biomass by 59% when compared to TME 1 in the unweeded plot. However, there was no significant difference in the weed biomass between the hand-weeded and herbicide-treated where TMS 30572 and TME 1 were cultivated. Root dry matter of TMS 30572 was higher by 72% when compared to TME 1 in the untreated field. However, there was no significant difference between the yield of TMS 30572 and TME 1 in both hand-weeded and herbicide-treated plots. In conclusion, TME 30572 is recommended for cultivation in regions with similar agroecological patterns coupled with Integrated Weed Management (IWM) especially, when planting TME 1 to obtain optimum yield. Keywords: Weed biomass, TMS 30572, TME 1, Yield, and Integrated Weed Management. DOI: 10.7176/JNSR/12-14-05 Publication date:July 31st 202

Three-dimensional carbon foam nanocomposites for thermal energy storage

This is the final version. Available from Elsevier via the DOI in this record.Nanocomposites consisting of paraffin/graphene nanoplatelets mix embedded in carbon foams via vacuum infiltration were fabricated with the aim of developing new phase change material (PCM) formulation with excellent shape stabilization, improved thermal conductivity and outstanding thermal reliability and structural stability. Physicochemical and thermal properties of the nanocomposites were evaluated using a suite of techniques such as scanning and transmission electron microscopy, X-ray diffraction, attenuated total reflection - Fourier transform infrared spectroscopy, nitrogen adsorption analyzer, differential scanning calorimetry, mechanical tester, Raman spectroscopy, thermal conductivity analyzer and thermogravimetric analyzer. The carbon foams exhibited good cyclic compressive behavior at a strain of up to 95% and kept part of their elastic properties after cyclic testing. Due to the robust mechanical integrity and layered meso-/macroporous morphology of these carbon foams, the nanocomposites are well equipped to cope with volume changes without leaking during thermal cycling. A 141% thermal conductivity enhancement observed for the carbon foam nanocomposite demonstrates the contributing role of the carbon foam in creating effective heat transfer through its conductive 3D network. The results have shown that proper chemical modification and subsequent carbonization of the low cost porous foams can lead to ultralight multifunctional materials with high mechanical and physical properties suitable for thermal energy storage applications.Engineering and Physical Sciences Research Council (EPSRC