Bridging Theory and Practice: Application of Constructivist Tenets to the Teaching of Reaction Stoichiometry

Active engagement of the learner with the learning environment, focusing on the learner rather than teacher, and acknowledging (as well as challenging) learners’ understanding/intellectual development are useful pedagogical strategies that can facilitate meaningful learning of reaction stoichiometry. In consonance with this fact, constructivist believed that students must play active roles in their learning if it is to occur deeply, endure, be enjoyable, and transfer to contexts beyond the classroom. Constructivism as a theory of learning is still gaining popularity as a new paradigm for learning science. Yet translating a theory of learning into a theory of teaching (before it can be operationalized) has proven to be quite difficult for teachers. This paper provides helpful insight into how constructivist instruction can be implemented when teaching reaction stoichiometry.Keywords: stoichiometric problems, problem-solving instruction, constructivist tenets, constructivism

Partial Purification and Characterization of Cellulase from the haemolymph of the African Giant Land Snail (Archachatina marginata)

The aim of this study is to partially purify and characterize the cellulase extracted from the snail haemolymph of the African giant land snail of the species, Archachatina marginata. The protein concentration of the haemolymph was found to be 168 mg mLG1 and the specific activity of the crude cellulase was found to be 0.007 U mgG1 protein using Carboxymethyl-cellulose (CMC) as the substrate. The partial purification on Sephadex G-200 produced two activity peaks. The molecular weights of the two cellulase fractions were estimated to be 112,202 and 67,000. The Michealis Menten constant (km) for cellulase was 4.3 and 2.8 mg mLG1 for the higher and lower molecular weight fractions, respectively. The multiplicity of cellulase complexes indicated that the haemolymph of A. marginata may convert derived cellulose in foodstuffs such as garlic, mushrooms and domestic wastes into sources of fuel. It is suggested that the enzyme can be used to produce value-added products, such as ethanol, citric acid, amino acids and vitamins including primary metabolites from cellulosic wastes

Effects of Deep-Fat Frying using Canola Oil, Soya Oil and Vegetable Oil on the Proximate, Vitamins and Mineral Contents of Unripe Plantain (Musa x paradisiaca)

Musa x paradisiaca (plantain) isamong the major tropical staple foods. This study was designed to determine the proximate, mineral and fat soluble vitamins constituents of unripe plantain fried with three different oils (canola oil, soya oil and vegetable oil) and unripe plantain oven dried sample was used as the control. The vitamins were determined using High Performance Liquid Chromatography (HPLC). The result of the proximate analysis showed that the dried samples had higher levels of protein (25.2%), carbohydrate (50.1%), moisture content (13.3%), ash content (2.02%), crude fibre (7.73%) but low level of crude fat in comparison with the fried samples. Plantain fried with vegetable oil had the lowest levels of protein (20.84%), carbohydrate (26.93%), moisture content (13.1%), ash content (1.72%) and crude fibre (6.57%) but the highest level of crude fat (30.84%). Plantain fried with vegetable oil had the highest level of calcium (211.80±0.1 mg gG1) while the dried plantain samples had high level of sodium (233.80±0.07 mg gG1). Lead (Pb) was absent in the dried plantain samples. Dried plantain samples gave a higher value of vitamins A (0.08±0.01 mg gG1), D (0.02±0.01 mg gG1), E (0.01±0.00 mg gG1), K (0.05±0.00 mg gG1) compared to plantain sample fried with canola oil which gave low level of vitamin D (0.03±0.00 mg gG1), E (0.25±0.00 mg gG1) and K (0.03±0.00 mg gG1). However, there was a very high level in vitamin A (0.72±0.02 mg gG1). The result showed that drying in oven retains the nutritional contents of plantain compared to deep-fat frying. Canola oil is recommended for frying although soya oil is also good

Semi analytic method for solving infectious disease model

In this paper, we present a deterministic model that captures the essential dynamics of infectious diseases. Differential Transform Method (DTM) is applied to attempt the series solution of the model. The efficiency of the DTM in solving the model is confirmed by classical fourth-order Runge-Kutta method implemented in Maple 18. The comparisons between the DTM and Runge-Kutta (RK4) solutions were made and there exists positive correlation between the results obtained by the two methods. The outcome of comparison between the DTM and RK4 validates the potential of the DTM in coping with the analysis of modern epidemics

Development of a Light Emitting Diode Lighting System with Power Factor Correction for Domestic Applications

The incandescent and fluorescent lighting systems which have been the most prominent electrical lighting choice for over 150 years are gradually being replaced in most homes with Light Emitting Diode (LED) Lighting Systems. This is due to their relatively low power consumption and good luminous intensity. LED lighting systems have revolutionized energy – efficient lighting. The significant feature of LEDs is that the light is directional with very low lagging power factor (0.2 – 0.6) as opposed to incandescent bulbs which spread the light more spherically with high power factor almost approaching unity. New LED designs address the directional limitation by using diffuser lenses and reflectors to disperse the light more. Since LED lighting represents a green technology, the issue of high power factor becomes very important. Power factor, defined as the ratio of real power consumed by a load (expressed in Watts) to apparent power (expressed in Volt-amperes), is a figure that ranges from zero to unity, it indicates the degree of distortion and phase shift in the current waveform. The work reported here proposes LED lighting system equipped with power factor correction driving circuit fed with dc – dc converter circuit. The power factor correction function is achieved by using switching converters circuit that operate directly from a full-wave rectified DC bus on a passive valley fill (PVF) circuit operating in Discontinuous Inductor Current Mode (DICM) for Power Factor Correction (PFC). This converter is simple to control, easy to construct and attractive for low cost application for domestic lighting. The results obtained have shown a LED lighting system with a lagging power factor of 0.85 that is energy – efficient compared to its conventional counterpart in domestic lighting applications

Partial Purification and Characterization of Cellulase from the Haemolymph of the African Giant Land Snail (Archachatina marginata)

The aim of this study is to partially purify and characterize the cellulase extracted from the snail haemolymph of the African giant land snail of the species, Archachatina marginata. The protein concentration of the haemolymph was found to be 168 mg mLG1 and the specific activity of the crude cellulase was found to be 0.007 U mgG1 protein using Carboxymethyl-cellulose (CMC) as the substrate. The partial purification on Sephadex G-200 produced two activity peaks. The molecular weights of the two cellulase fractions were estimated to be 112,202 and 67,000. The Michealis Menten constant (km) for cellulase was 4.3 and 2.8 mg mLG1 for the higher and lower molecular weight fractions, respectively. The multiplicity of cellulase complexes indicated that the haemolymph of A. marginata may convert derived cellulose in foodstuffs such as garlic, mushrooms and domestic wastes into sources of fuel. It is suggested that the enzyme can be used to produce value-added products, such as ethanol, citric acid, amino acids and vitamins including primary metabolites from cellulosic wastes

Voltage Stability Assessment on a Distribution System without Wind Turbine Generators Connected

This work investigates the healthiness of the Nigeria distribution grid (the test system) to accommodate the connection of wind turbine generators. The test distribution system is subjected to load-flow analysis; the program was developed in Matlab platform without wind turbine connection. This is necessary to know if the system voltages at each bus remain within specified limits and angle at each bus. The ability of a site to sufficiently accommodate wind generation does not only depend on wind speeds but its ability to interconnect to the existing grid. That is, it is not enough to say that the wind turbines should be connected to the grid just because there are sufficient wind speeds to drive the wind turbine, but the wind turbine generators must be able to connect with the existing grid (which must be healthy enough to accommodate the wind turbine generator).The result shows that the voltage magnitude at each bus is within the specified limit which shows that the network is healthy without wind turbine generators connected. The findings in this research work will give much better insight to potential investors in wind power in Nigeria

Evaluation of Lifetime Cancer Risk in Some Vegetables and Soil Samples in Two Main Cities in Ogun State: Human and Ecological Risk

The spate of health challenges via the ingestion of radionuclides is still of concern especially in regions that have no clear documentation 14 of background of radioactive sources. The present study evaluated the activity concentrations of naturally occurring radioactive nuclides 15 in plants and their corresponding soil collected at Ibeshe and Covenant University community areas of Ogun State, Nigeria. The activity 16 concentrations and other radiological risks from consuming the leafy vegetables were also estimated. The results show that the mean 17 concentration of 226Ra, 232Th, 40K in the agricultural soil were found to be 24.18±2.31, 20.93±2.27, 20.95±1.9 for Ibeshe and 58.76±4.84, 18 26.06±1.93, 33.87±2.23, respectively for Covenant University. Whereas, for the leafy vegetables, the mean concentration of 226Ra, 232Th, 19 40K were found to be 5.02±0.9, 7.98±1.70, 427.82±29.75 for Ibeshe and 17.57±2.35, 22.19±3.0, and 424.17±25.15 for Covenant 20 University Community. In comparison, all these values are within the recommended limits of 32.00 and 45.00, 420.00, Bqkg-1for 226Ra, 21 232Th, 40K according to the United Nations Scientific Committee on the Effect of Atomic Radiation (UNCEAR) except the mean value 2 for Covenant University soil for 232Th which is slightly higher. The values obtained were comparable 22 to the internationally recommended 23 values. The mean value for excess lifetime cancer risk (ELCR) for Ibeshe North is 31.08, while that of Canaanland (CU) is 239.03, 24 respectively is lower than the recommended limits of other published papers 1.72 x 104 according to International Commission on 25 Radiological Protection (ICRP). These lower radiological risks indicate apparently that the chemical carcinogenic pollutants in the 26 samples may be the major risk, inducing chemical parameters in the study area. This study will serve as a baseline data for any 27 radiologically induced diseases. Significantly, it will serve as a baseline data for any radiologically induced diseases from vegetables in 28 Nigeria and suggests further research on chemical toxicity risks on the same samples

Nasal carriage of methicillin resistant Staphylococcus aureus among medical students of a private institution in Ilishan-Remo, Ogun State, Nigeria

Background: Nasal carriage of methicillin resistant Staphylococcus aureus (MRSA) is a major factor for its transmission especially from the health workers and medical students to their patients. There are a number of published data on the prevalence of MRSA among health workers but data on nasal colonization of medical students by MRSA are sparse in Nigeria. The objectives of this study are to determine the prevalence of nasal carriage of MRSA among medical students of the Ben Carson School of Medicine, Babcock University, Ilishan-Remo, Ogun State, Nigeria, and identify risk factors associated with this nasal carriage. Methodology: A case control study involving 100 clinical (study group) and 100 pre- clinical (control group) medical students was undertaken between March 2018 and October 2019. Structured questionnaire was administered to obtain socio-demographic information and potential risk factors. Nasal swab was collected from each student and cultured for isolation of S. aureus by standard microbiology techniques. Phenotypic MRSA was detected by the cefoxitin 30μg disk diffusion method according to the guideline of Clinical and Laboratory Standards Institute. The mecA gene was detected by conventional polymerase chain reaction (PCR) assay. Results: The prevalence of S. aureus nasal carriage among the study group was 14% (14/100) while the prevalence among the control group was 6% (6/100) (p=0.097). The prevalence of phenotypic MRSA among the study group was 4% (4/100) and 1% (1/100) among the control group (p=0.3687) while mecA gene was detected in 3 of the 4 (75%) phenotypic MRSA positive study participants and in the only (100%) phenotypic MRSA positive (1%) control group. Antibiotics usage without prescription, antibiotic treatment of common cold, and use of antibiotics in the previous one year, were significantly associated with MRSA carriage among the study group. Conclusion: Although the prevalence of nasal carriage of S. aureus and MRSA among clinical and pre-clinical medical students was not statistically significant, the risk factors identified with carriage of MRSA among the study group indicates the need for antimicrobial stewardship program to reduce carriage and transmission of MRSA by medical students. Keywords: methicillin resistant, Staphylococcus aureus, mecA gene, nasal carriage, medical student

Climate change adaptation options in farming communities of selected Nigerian ecological zones

This chapter examines the impacts of climate change on three tropical crops and assesses the climate change adaptation options adopted by rural farmers in the region. The study was conducted among farming communities settled in three major ecological zones in Nigeria. Over 37 years of data on rainfall and temperature were analyzed to examine climate change impacts on three major crops: rice, maize, and cassava. Farmers' adaptive capacity was assessed with a survey. Climatic data, crop yields, and survey data were analyzed using both descriptive and inferential statistics. The relation between rainfall/temperature and crop yields was examined using the Pearson correlation coefficient. Results show a high variation in the annual rainfall and temperature during the study period. The major findings from this research is that crops in different ecological zones respond differently to climate variation. The result revealed that there is a very strong relationship between precipitation and the yield of rice and cassava at p <0.05 level of significance. The results further showed low level of adaption among the rural farmers. The study concludes that rainfall and temperature variability has a significant impact on crop yield in the study area, but that the adaptive capacity of most farmers to these impacts is low. There is a need for enhancing the adaptation options available to farmers in the region, which should be the focus of government policies