An Alternative Stratified Cox Model for Correlated Variables in Infant Mortality

Often in epidemiological research, introducing a stratified Cox model can account for the existence of interactions of some inherent factors with some major/noticeable factors. This paper aims at modelling correlated variables in infant mortality with the existence of some inherent factors affecting the infant survival function. A Stratified Cox model is proposed with a view to taking care of multi-factor-level that has interactions with others. This, however, is used as a tool to model infant mortality data from Nigeria Demographic and Health Survey (NDHS) with g-level-factor (Tetanus, Polio and Breastfeeding) having correlations with main factors (Sex, infant Size and Mode of Delivery). Asymptotic properties of partial likelihood estimators of regression parameters are also studied via simulation. The proposed models are tested via data and it shows good fit and performs differently depending on the levels of the interaction of the strata variable Z*. An evidence that the baseline hazard functions and regression coefficients are not the same from stratum to stratum provides a gain in information as against the usage of the Cox model. Simulation result shows that the present method produces better estimates in terms of bias, lower standard errors, and or mean square errors

Development and Validation of Scientific Literacy Achievement Test to Assess Senior Secondary School Students’ Literacy Acquisition in Physics

Physics literacy plays a crucial part in global technological development as several aspects of science and technology apply concepts and principles of physics in their operations. However, the acquisition of scientific literacy in physics in our society today is not encouraging enough to the desirable standard. Therefore, this study focuses on development and validation of scientific literacy achievement test to assess senior secondary school students’ literacy acquisition in physics. The study adopted descriptive survey research design in which a total of two hundred and six (206) students from 8 secondary schools in Ibadan North and Oorelope local government areas of Oyo state were assessed. The schools were selected using proportional random sampling techniques. The achievement test titled, Physics-Scientific Literacy Achievement Test (P-SLAT) that had been validated by experts and tested to have Cronbach’s alpha and Split-half reliability coefficient of 0.82 and 0.80 respectively. The result of the administered test was collated and coded for analysis, which was carried out with the aid of SPSS 17 package and Microsoft word excel while both descriptive, such as simple percentage and charts were adopted. The result of the research findings shows that. The overall acquisition of scientific literacy in physics among the students is average. The achievement test used has an average reliability coefficient of 0.70 based on Cronbach’s alpha, Kuder-Richardson (KR20) and Split-Half method. Based on the three psychometric properties (reliability, item difficulty and discrimination) considered in item analysis of the achievement test developed in the study, eighteen (18) items which is equivalent to 72% of the total items form the validated achievement test.These findings provide vivid evidence for recommendations for various examining bodies by subjecting multiple choice items to psychometric tests to ascertain and improve items’ quality in order to obtain a reliable and valid test result. It was also suggested for prospective researchers in the same or related field of study that this research should be carried out in all secondary schools in Oyo state in order to have a more generalised result on the level of secondary school students’ acquisition of scientific literacy in physics. Keywords: Scientific literacy, Item analysis, difficulty index, discrimination index, reliability coefficient

Evaluating the Effectiveness of Maintenance Practice: Case Study of a University Power Generating Plant Unit

The study was conducted in one of the Federal universities in Nigeria. The aim was to evaluate the effectiveness of the maintenance practicesin a power generating plant usinganavailability ratio method. The plant was placed under studyfor a period of six months.The operation records were obtained from which the availability ratio was obtained. Questionnaires were also distributed to the 21staff members in the unit and oral interviews were conducted to ascertain the maintenance strategy practiced by the unit. The study revealed that the unit has an availability of 61%,which is low compared to the standard availability ratio of power generating plants(99.9%). The maintenance practices of the unit weredeterminedineffective. Thisineffectiveness was attributed to poor documentation, low-skilled manpower, lack of a spare parts stock, and deficient operating maintenance strategy,as well aspoor maintenance funding and management policy. The study recommended autonomy of the maintenance unit, a betterinventory system for work materials and spare parts, practice of a predictive or condition monitoring maintenance strategy, training and retraining of the workforce and acquisition of relevant equipment,such as vehicles and computers,as measures that will, in part, improve the effectiveness of maintenance of the plant. The recommendationsof this study can be applied to the power sector in Nigeria,which is consideredby many to be grossly ineffective

Plastination: a novel approach to cadavar scarcity in Nigeria

Cadaveric dissection has always been an integral part of medical education being used for teaching Anatomy, Surgery, Pathology, Radiology, Medical and Biomedical Research in Nigeria higher institutions of learning. However, it is undeniable that Nigeria Universities had been facing a lot of challenges in acquiring cadavers. In view of this scarcity of bodies, organs and tissues for studies, teaching and research, newer techniques of preserving biological tissues for long duration such as plastination is important. Thus, this review elaborates and identifies problems in cadaver acquisition in Nigeria, suggests better preservative technique of cadaver and identifies possible limitations to the practice of the suggested technique and proper possible solutions to the limitations.Keywords: Plastination, Cadaver, Anatomy, Preservativ

Optimization of operating parameters of novel composite adsorbent for organic pollutants removal from POME using response surface methodology

The present work aimed to develop a novel composite material made up of activated cow bone powder (CBP) as a starting material for reducing chemical oxygen demand (COD) and ammonia-nitrogen (NH3eN) from palm oil mill effluent (POME). The optimization of the reduction efficiency was investigated using response surface methodology (RSM). Six independent variables used in the optimization experiments include pH (4e10), speed (0.27e9.66 rcf), contact time (2e24 h), particle size (1e4.35 mm), dilution factor (100e500) and adsorbent dosage (65e125 g/L). The chemical functional groups were determined using Fourier transform irradiation (FTIR). The elemental composition were detected using SEM-EDX, while thermal decomposition was investigated using thermo gravimetric analysis (TGA) in order to determine the effects of carbonization temperature on the adsorbent. The results revealed that the optimal reduction of COD and NH3eN from raw POME was observed at pH 10, 50 rpm, within 2 h and 3 mm of particle size as well as at dilution factor of 500 and 125 g L�1 of adsorbent dosage, the observed and predicted reduction were 89.60 vs. 85.01 and 75.61 vs. 74.04%, respectively for COD and NH3eN. The main functional groups in the adsorbent were OH, NeH, C]O, C]C, CeOeC, CeOeH, and CH. The SEMEDX analysis revealed that the CBP-composite has a smooth surface with high contents of carbon. The activated CBP has very stable temperature profile with no significant weight loss (9.85%). In conclusion, the CBP-composite investigated here has characteristics high potential for the remediation of COD and NH3eN from raw POME

Assessment of fishing gear and crafts utilized by fishermen in Eleyele Lake, Ibadan, Oyo State

The study was conducted to assess the evolution of fishing gears and crafts utilized by fishermen in Eleyele lake reservoir in lbadan Nigeria. Data were collected from thirty fishermen using a structured questionnaire. The data obtained were analyzed using counts and chi-square. Majority (56.7%) of the respondents were married, more of respondents were male (56.7%). Fish and fishing gear construction activities in the study area is dominated by youth. More of the respondents were Christians and few were Muslims (36.7%). There was significant relationship between the type of fishing gear use (modern and traditionl) and the time spent to catch fish as well as the quantity of fish caught. The result also revealed that traditional fishing gears such as bamboo trap, hook and line and cast net were been used by the fisher folks but were later changed to modern fishing gear. However, the effectiveness and efficiency of the modern fishing gear is being hampered by aquatic weed covering the surface of the water

Synthesis, physico‑mechanical and microstructural characterization ofAl6063/SiC/ PKSA hybrid reinforced composites

The utilization of agro-residues ash as complementary reinforcing materials continues to gain prominence for metal matrix composite (MMCs) development. A rarely investigated but largely available ash among these agro-residues is the palm kernel shell ash (PKSA). Thus, the present study investigates the influence of PKSA particulates hybridized with SiC on the physico-mechanical properties and microstructure of Al6063 metal composites. The composites are synthesized using the double stir-casting technique with SiC held constant at 2 wt.%, while the PKSA contents are varied from 0 to 8 wt.%. The phases present and morphology of the composites are investigated using X-ray diffractometer (XRD) and scanning electron microscopy (SEM), respectively. The density, porosity, hardness, tensile and fracture toughness tests are carried out on the hybrid composites. X-ray diffractometer revealed that for Al 6063, only Al cubic crystal system was identifiable within the matrix. However, for the reinforced composites, major phases identified are Al, Fe(3)Si, SiC, MgO, and SiO(2). The SEM images show that the particulates reinforcements (SiC and PKSA) were uniformly dispersed in the matrix. The percentage porosity for the composites ranged from 2.06 to 2.39%. In addition, hardness, yield strength and ultimate tensile strength of the composites are about 10.3%, 18.5% and 10.4%, respectively better than for Al 6063. However, the percent elongation and fracture toughness are lower for the hybrid composites than for Al 6063 and SiC reinforced composite with values decreasing with increase in ash content. Hence, the MMCs produced will be applicable for light-weight engineering applications

Influence of temperature on the chemical compositions and microstructural changes of ash formed from palm kernel shell

This study investigated the characteristics of raw palm kernel shell (raw PKS) and the influence of temperature variation on palm kernel shell ash (PKSA). The PKSA was obtained under different temperature regimes of 900, 1000, and 1100�C. The characterization of the samples was carried out using X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) with attached Energy Dispersive X-ray (EDX) facilities. The results showed that moisture and ash contents and the density of raw PKS were 6.56%, 8.86%, and 745 kg/m3 , respectively. The colour of the pulverized PKS was dark brown, as observed by visual examination based on standard colour gradation. This colour transformed into various shades of brown when PKS was subjected to different temperature regimes to form PKSA. The XRF analysis showed that silica is the main constituent of the raw PKS and PKSA samples. Silica content in the PKSA increased with the rise in the heating temperature. The FTIR and EDX spectra confirmed the predominance of silicon compounds with functional groups associated with silanol and siloxane. Also, XRD analysis revealed that the silica contents in the samples are quartz, while SEM examinations indicated that temperature increases during processing influenced the microstructure through the reduction of pore concentration in the samples. The silica obtained from the PKSA would find applications in metal matrix composites as partial reinforcing material

Impact Of Covid-19 Pandemic Lockdown on Social and Mental Health of ondo State Residents, Nigeria

COVID-19 is a pandemic disease which has caused fears and concerns among many people, with a significant influence on social and mental well-being. Considering this, this study investigated the impact of COVID-19 pandemic lockdown on social and mental health of Ondo State residents, Nigeria. Descriptive survey design was used in this study. Using multistage sampling technique, data were obtained through administration of questionnaire on 648 married couples with children in Ondo State. Data collected were analysed using inferential statistics. Findings revealed that respondents disclosed that their income and earnings have drastically reduced (X̄ = 2.89), feel withdrawn from community participation (X̄ = 2.96), reduced their interaction with people (X̄ = 2.98), reduced their interaction with their loved ones (X̄ = 2.67). The impact of COVID-19 lockdown on the mental health of the residents indicated that majority of the respondents feel lonely due to COVID-19 lockdown (X̄ = 3.00), feel distressed (X̄ = 2.87) and agitated (X̄ = of 2.47). The study revealed a significant difference in the social and mental health of Ondo state residents based on their age and gender; F (5, 642) = 10.554, p<.05, ɳ2 =.076; F (5, 642) = 6.694, p<.05, ɳ2 =.000 respectively. Hence, the impacts of the COVID-19 lockdown on the social and mental health of majority of the respondents was obvious. Therefore, health education awareness raising activities on mass media should be urgently conducted with focus on how people can cope effectively with their social and mental health during this lockdown period. &nbsp

Fabrication and Evaluation of Screw-like Fish Pelletizer

Good and balanced meals are required for fish to stay healthy and the production of these meals requires some machines like pelletizer. This study therefore contributes to the improvement of existing models of this machine by designing, fabricating and evaluating the performance of a new pelletizer. After fabrication, 5 kg fish feed ingredients weight was processed for 2.5 minutes in the machine in quadruplicate. The average discharge efficiency, percentage loss due to residue ingredients and production rate for the machine are 92.25 %, 7.75 % and 110.7 kg/h, respectively. The results showed that an increase in drying days led to a corresponding increase in percentage moisture content removal with a similar reduction in the weight of the pelletized fish meal. This machine will be of great assistant to medium and small-scale aquaculture farmers, thereby reducing the need for foreign sources of fish feed in fish farming sector