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Variation in Prices of Food Items in Jamaica: An Exploratory Analysis of Pricing Mechanisms of Supermarkets in Kingston
Get PDFThe Jamaica Agriculture Market Information System reports wide variations in the price of similar food items across supermarkets in the capital city, Kingston. Possible explanations for this phenomenon are explored in this paper. Our findings indicate that supermarkets that practice price smoothing are more likely to persistently sell food items at the highest price. Likewise, supermarkets that are centrally located are prone to consistently have the highest price for food items. Whether or not farmers who supply food items to the supermarkets and consumers who buy from them are sensitive to price smoothing will provide validation for this practice by supermarkets. This constitutes an area of future study
Soil DNA Purification and Isolation
Get PDFThere is an increased interest in the extraction of nucleic acids from various environmental samples, since molecular techniques allow less biased access to a greater portion of uncultivable microorganisms. Two strategies have been developed to improve DNA recovery in terms of yield, purity and unbiased representation of the microbial diversity. Amplification of DNA from soil is often inhibited by co-purified contaminants. DNA is also suitable for PCR amplification using various DNA targets. This review presents an overview of the available methods to achieve this challenging objective. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol precipitation
Adjustment and Gross Errors Detection of Free Triangulation Geodetic Network Using Minimum-Norm Least-Squares Inverses and Data Snooping
Get PDFWe utilise minimum-norm least-squares based on the indirect observations methods to adjust our 2-dimensional triangulation network. The main objective of this paper is to optimally adjust the approximate coordinates of the nodes (points) of the given network. The network observations (11 measured distances and 17 angles) have been adjusted by being combined in linear system of equations in terms of free-network adjustment procedure to rigorously adjust the approximate coordinates over the network points. We obtained better converged values by applying an iterative procedure, the minimum corrections for the free-network coordinates are obtained after a number of five iterations. The data snooping procedure has been used to test the reliability and precision of the network observations. The T-Test criterion is then applied for gross error detection, five angles and two lines are suspected to include gross errors at a critical value of 1.98
Reducing Energy Use and Costs in Agriculture
Get PDFAgriculture and the related primary industry is an increasingly energy demanding sector. Energy is needed to different extent in all the stages of the agri-food chain. In many cases, energy cost may represent a significant proportion of the total agricultural production cost, including the cost of manufacturing and transportation of various chemicals and fertilisers. A modified and standardized energy analysis and benchmarking process is described in this paper. It is shown that energy use in agriculture varies considerably, depending on the cropping enterprise and the farming systems. Opportunities to reduce energy use and costs and greenhouse gas emissions in agriculture are discussed
Municipal Solid Waste (MSW) Organic Fraction to Energy. Cuban Case Study. Brief Considerations
Get PDFThis article aims at describing and reports current issues related to the management of MSW organic fraction to energy in Cuba. The paper firstly approach those latest advancements on biochemical based technologies capable of converting MSW organic fraction to energy in a reasonable efficient and economic way, based on analysis of currently widely used biochemical based processes. Lately the paper briefly delves with Cuban previous modest experience in converting solid waste to energy as well as composting residues exiting from already installed bioreactors. Updating of the country's current solid waste to energy facility should be approached in the future
Optimizing the Inclination Angle of a Solar PV System for Installation in Slave Lake, Alberta, for Maximizing PV Power Generation
Get PDFIncreasing fossil fuel prices, electricity demand, and global concern for greenhouse gas emissions have generated an increase in research of novel renewable energy technologies for green power generation. Renewable solar-photovoltaic (PV) systems are known fosr their ability to directly convert the solar energy into electrical energy for locations where there is a desperate need and demand for electrical power, e.g. Communities and towns in remote locations, and solar energy is available. PV systems tend to generate more power if they are operated efficiently. The inclination (tilt) angle at which a solar photovoltaic (PV) module is sloped from the horizontal plane is one of the most influencing system parameters that affects the electrical power output from the PV system. This is due to the fact that the variation in the tilt angle affects the amount of incident solar radiation received on a PV system and utilized by the load once installed at a certain site. In this work, a mathematical model is used to estimate the total solar radiation incident on an inclined surface and to determine the optimum inclination angle for maximizing power generation from a solar PV system installed in Slave Lake, Alberta, Canada. The total solar energy received on the optimally inclined PV surface is computed for all months in a year. It was found that the monthly average optimum tilt angle of the PV system varied from a minimum value of 9o in the month of June to a maximum value of 78o in the months of January and December. The yearly average monthly optimum tilt angle for the fixed PV system in Slave Lake was estimated to be at 47o. It was also found that the highest maximum incident radiation of approximately 21.30 Mj/m2 for the whole year occurred in the month of June, where as approximately 30.4% of this value (the lowest in the year) occurred in the month of December. The minimum incident solar radiation for all months in the winter season occurred at almost zero tilt angle and that the variation of the monthly average daily sunlight hours varied from 6.9 hours in December to as high as 17.1 hours in June
Female Students’ Fear of Crime and It’s Correlation with the Environmental Features of the Campus
Get PDFThe purpose of this study is to create safer campus outdoor spaces for female students during the night. For this, a literature review, a mapping survey of criminally vulnerable spots, and a questionnaire were carried out to derive the environmental characteristics affecting the fear of crime and to measure the fear of crime felt by female students at the outdoor spaces of campus. Based on the survey, the correlation between the fear of crime of female students and environmental characteristics of outdoor spaces was analyzed. This study is significant in suggesting ways to alleviate the female students' fear of crime in the college campus
Photocatalytic Oxidation Kinetics for Desulfurization of Dibenzothiophene with Al2O3/g-C3N4 Heterojunction
Get PDFAl2O3/g-C3N4 heterojunction is fabricated for the photocatalytic removal of dibenzothiophene in oil-water biphasic system and the reaction kinetics is studied. The influences of Al2O3/g-C3N4 ratio and photocatalyst dosage on reaction rate constant are investigated. The results indicate that the optimum addition of Al2O3/g-C3N4 composite is 0.075 g in 100 mL reaction system and the photooxidation kinetics of dibenzothiophene follows first-order reaction. The sulfur removal of dibenzothiophene can reach 90.3 % in 4 h under the irradiation of mercury lamp and the sulfur content can be decreased from 200 to below 20 ppm
Amplitude Variation with Offsets and Azimuths Simultaneous Inversion for Elastic and Fracture Parameters
Get PDFAzimuthal elastic inversion or AVO/AVA analysis has proven to be effective for fracture description and stress evaluation in unconventional resource plays. Fracture weakness including normal and tangential weakness from linear slip theory bridge the seismic data and fracturing parameters as intermediate parameters. However, the stability of the azimuthal elastic inversion methods available for anisotropic parameters or fracture parameters in field data remains challenging. This study explores a practical azimuthal simultaneous elastic inversion method in heterogeneous medium for fracture weakness estimation. Taking the heterogeneity and anisotropy of fracture media into consideration, and based on perturbation theory and stable phase approximation, the fracture medium can be considered as the superimposition of background medium and perturbation medium, and then the seismic scattering coefficient of fracture media can be derived. This equation establishes the relationship between seismic data and fracture weakness together with elastic parameters like P-wave and S-wave moduli and weaknesses. With this equation, a heterogeneous inversion method is proposed. This method implements the estimation of P-wave and S-wave moduli and fracture weaknesses simultaneously, and the constraint from initial model and multi-iterations enhances the stability of this method. In this approach, the parameters of the perturbation medium are initially estimated, and then they can be superposed to the parameters of the known background medium as the renewal parameters of the background medium in next iteration. We can yield the final estimation of the parameters in heterogeneous medium after several iterations when the last two estimated results are similar. Model test and field data examples verify the feasibility and potential of the proposed approach
Change of Staphylococcus Aureus and Salmonella During Storage Period of Food Wastes in China
Get PDFood wastes, such as animal feedstuff, may result in risks of disease spreading. Changes of Staphylococcus aureus and Salmonella in the food wastes during storage period were investigated in this paper. Staphylococcus aureus were tested by plate count and coagulase test, and Salmonella were tested by plate count and PCR assay. Results showed that both Staphylococcus aureus and Salmonella existed in the food wastes. After 48 h storage at 20 oC and 37 oC, the amount of Staphylococcus aureus decreased from 103 - 105 CFU/g to 102 and 0 CFU/g respectively. The amount of Salmonella decreased from 5.5x106 - 4.6x107 CFU/g to a range between 2.0x104 and 2.0x105 CFU/g after 48 h storage at 20 oC, and it was less than 20 CFU/g after 48 h storage at 37 oC. The two pathogenic bacteria would be restricted by pH decrease, which was caused by the fermentation of the food wastes