Application of Integer Programming for Mine Evacuation Modeling with Multiple Transportation Modes

The safe evacuation of miners during an emergency within the shortest possible time is very important for the success of a mine evacuation program. Despite developments in the field of mine evacuation, little research has been done on the use of mine vehicles during evacuation. Current research into mine evacuation has emphasized on miner evacuation by foot. Mathematical formulations such as Minimum Cost Network Flow (MCNF) models, Ant Colony algorithms, and shortest path algorithms including Dijkstra's algorithm and Floyd-Warshall algorithm have been used to achieve this. These models, which concentrate on determining the shortest escape routes during evacuation, have been found to be computationally expensive with expanding problem sizes and parameter ranges or they may not offer the best possible solutions.An ideal evacuation route for each miner must be determined considering the available mine vehicles, locations of miners, safe havens such as refuge chambers, and fresh-air bases. This research sought to minimize the total evacuation cost as a function of the evacuation time required during an emergency while simultaneously helping to reduce the risk of exposure of the miners to harmful conditions during the evacuation by leveraging the use of available mine vehicles. A case study on the Turquoise Ridge Underground Mine (Nevada Gold Mines) was conducted to validate the Integer Programming (IP) model. Statistical analysis of the IP model in comparison with a benchmark MCNF model proved that leveraging the use of mine vehicles during an emergency can further reduce the total evacuation time. A cost-savings analysis was made for the IP model, and it was found that the time saved during evacuation, by utilizing the IP model, increased linearly, with an increase in the number of miners present at the time of evacuation

Nonparametric efficiency and productivity change measurement of banks with corporate social responsibilities : the case for Ghana

This thesis has twofold objectives. The first is to develop a framework based on the existing theory and method of Data Envelopment Analysis (DEA) for measuring performance of financial firms that have the dual goals of profit maximisation and Corporate Social Responsibilities (CSRs). The second is to examine the impact of banking regulatory reforms including bank ownership, specialisation, and capitalisation types on the average efficiency and frontier differences of banking subgroups. The objectives are achieved using the standard DEA, the metafrontier analysis and the global frontier differences (GFD). DEA can handle multidimensional inputs and outputs without specifying specific functional forms. CSR is conceptually justified and modelled as an additional output into the banking intermediation approach. Two DEA models, one with CSR and another without CSR are measured and compared. Parametric and nonparametric tests and regressions are utilised to support, empirically, the relevance of CSR in bank performance evaluation. Do foreign banks outperform private-domestic and state banks? Should banks diversify their products or focus in narrow range of products and services? Are listed banks more efficient than non-listed banks? The second part of the thesis contributes to the extant literature by answering these questions using the metafrontier analysis and the GFD to provide new evidence on the effect that the entry of foreign and private-domestic banks, universal banking and listing of banks on the stock market, have on bank performance. Banks are segmented into groups based on their bank-specific attributes and their average efficiencies and bestpractice differences compared. Relevant policy recommendations are drawn from the analysis for both the banking regulator and bank management. The final methodological contribution extends the GFD by defining a further decomposition of the global frontier shift, into components that indicate whether an observation is situated in a more or less favourable location in the production possibility set. Consequently, a four-factor “Newly-decomposed Malmquist productivity change index” is proposed. The index and its decompositions have potentially interesting policy implications, which are illustrated using the empirical data on Ghanaian banks. The index is in the spirit of the standard Malmquist index but the intuition is that some components can be used to draw conclusions about productivity changes for a whole population of firms whilst others determine whether individual firms are in favourable locations and/or moving towards locations that are more favourable over time. More importantly, arguably, a listed, universal or foreign bank can be located in a favourable position and move towards location that is more favourable by virtue of its bank-specific attributes or by contributing more towards CSR. These factors are explored and policy measures prescribed in the final contribution of the thesis

Computational modeling of expanded plasma plumes in vacuum and in a tank

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1999.Includes bibliographical references (leaves 143-149).Electric propulsion devices have shown to offer substantial fuel savings for various space missions. Hall thrusters, specifically, have shown great promise over the years due to their near optimum specific impulse for a number of space missions. The Hall thruster, however, releases a partially ionized plasma plume which contaminates any surface it comes into contact with. Backflow contamination can lead to sputtering and effluent deposition on critical spacecraft components. A computational method for studying these interactions was developed by David Oh in 1997. He developed a Particle-in-Cell and Direct Simulation Monte Carlo (PIC-DSMC) algorithm to model the expansion of a plasma plume from a Hall thruster into a vacuum. In his work he implemented a plasma-surface interaction model which determined erosion rates on surfaces made of quartz, silicon and silver but he did not track the surface material removed. In this work Oh's model is expanded to include the removal and tracking of material from generic spacecraft surfaces and the walls of a vacuum tank. Sputtering yields adopted in this model are based on sputtering theory developed by Matsunami and Yamamura. Since the plasma can have a negative impact on spacecraft subcomponents, a method for protecting the spacecraft (in the form of a protective shield) is proposed, studied, and recommendations are discussed.by Bernard K. Asare.S.M

The Level of Existence and Impact of Cost and Time Overruns of Building Construction Projects in Ghana

The construction industry has over the years been challenged with cost and time overruns of construction projects all over the world including Ghana. This problem has become a major concern to all the stakeholders of construction industry in Ghana. This study attempts to identify and establish the level of existence of cost and time overruns of building construction projects in Ghana, its causes and its relative effect on the construction industry and offers recommendations to minimize or curbs it. A survey which relied heavily on questionnaires was used to elicit opinions from Quantity Surveyors, Architects and Project/Construction Managers in key institutions in the Ghanaian construction industry such as client organisations, contracting firms and consulting firms. The purposive, convenience and snowball sampling techniques were used and out of 120 questionnaires distributed, 89 were received. The findings showed that cost and time overruns exist in more than 40% of building construction projects in Ghana. It was also identified and established that cost and time overruns of building construction projects in Ghana exceed 40% of estimated project cost and time. It was further established that, public building construction projects in Ghana had an alarming average cost and time overruns of 75% and 146% respectively with a maximum limits of cost and time overruns of 376% and 400% respectively, whereas, private building construction projects in Ghana, rather had a relatively lower average cost and time overruns of 34% and 77% respectively, with maximum limits of cost and time overruns of 98% and 300% respectively. The study further identified 34 and 38 significant causes of cost and time overruns respectively, as well as 15 significant effects. This study has not only filled the gap in existing literature on the subject in Ghana, but has also made recommendations which will improve and minimize the occurrence of cost and time overruns of construction projects in Ghana. Keywords: Level of Existence, Impact, Cost Overrun, Time Overrun, Building Construction Project

Automatic Multiple Choice Examination Questions Marking and Grade Generator Software

This paper discusses a feasible software solution that enables automatic marking andgrading of scripts. Technology keeps expanding, and more advanced innovations arebeing implemented with time. The marking and allocation of grades for examina-tion scripts through human efforts are gradually becoming a thing of the past. Hence,machines and software applications are introduced to make the entire marking andgrading of examination scripts more efficient, fast, and less tedious. Computer visionis an artificial intelligence (AI) knowledge domain that ensures devices obtain usefulinformation from digital images, videos, and other visual inputs. Image processingand recognition, a unique part of computer vision alongside the python program-ming language and the OpenCV library was employed for this project. These are themost used in developing most recent applications that utilize, to some extent, arti-ficial intelligence to attain specific desired results. The result of the project seeksto develop a maintainable android software application that uses image processingtechnology to scan patterns or images and grades results of multiple-choice questionscripts based on a set marking scheme. This ensures that desired results are obtainedwhile increasing efficiency and productivity

Urinary Lysosomal Enzyme Activities and Albuminuria in Ghanaian Patients with Type 2 Diabetes Mellitus.

Renal tubular lysosomal enzyme activities like alanine aminopeptidase (AAP) and N-acetyl-β-D-glucosaminidase (NAG) have been shown to increase in patients developing diabetic nephropathy and nephrosclerosis. This study aimed to determine the activities of N-acetyl-β-D-glucosaminidase and alanine aminopeptidase and albumin concentration in urine samples of patients with type 2 diabetes. One hundred and thirty (65 type 2 diabetic and 65 nondiabetic) subjects participated in this study. Blood samples were drawn for measurements of fasting blood glucose, albumin (Alb), lipids, and creatinine (Cr). Early morning spot urine samples were also collected for activities of alanine aminopeptidase (AAP), N-acetyl-β-D-glucosaminidase (NAG), and concentration of albumin (U-Alb) and creatinine (U-Cr). Both NAG/Cr and AAP/Cr were significantly increased in diabetic subjects compared to controls (p < 0.001). There was positive correlation between NAG/Cr and Alb/Cr (r = 0.49, p < 0.001) and between NAG/Cr and serum creatinine (r = 0.441, p < 0.001). A negative correlation was found between NAG/Cr and eGFR (r = -0.432, p < 0.05). 9.3% and 12% of diabetics with normoalbuminuria had elevated levels of AAP/Cr and NAG/Cr, respectively. We conclude that measuring the urinary enzymes activities (NAG/Cr and AAP/Cr) could be useful as a biomarker of early renal involvement in diabetic complications

Assessment of fetal wastage in pigs slaughtered at Kumasi abattoir, Ghana

There had been dearth of information on the level of fetal wastages in slaughtered pigs in West African countries other than Nigeria. This study evaluates the fetal losses due to slaughtering of pregnant pigs at the Kumasi abattoir in Kumasi, Ghana. The ages of the fetuses were estimated using standard technique with the influence of sex, age and breed of pig on fetal loss being evaluated. Data were subjected to descriptive and quantitative analysis. 2817 pigs were slaughtered during the period of the study with a monthly average of 563.1739(61.73%) were sows and 430(29.27%) were pregnant. 141(28.20%) sows were slaughtered in January, constituting the highest throughout the period of the study with corresponding fetal loss of 616(76.60%). Most of the fetuses wasted in this study were recorded in the second and third trimester (83.51%). The percentage of fetal wastage (the total number of fetuses wasted divided by the total number of pigs slaughtered) was 2117(75%) in this study. The results revealed high incidence of fetal losses at the Kumasi abattoir. There is need to advocate for routine veterinary checks and interventions in order to reduce the high level of fetal wastage which call for strategic planning and decision-making on animal food security in Ghana.Keywords: Abattoir, Fetal wastage, Slaughtered pigs, Ghan

Case Report: A case of?dipylidiasis in a?first-trimester pregnant woman attending a routine antenatal clinic at?Elmina health centre, Ghana

Dipylidiasis is a zoonotic parasitosis caused by a canine and feline tapeworm, Dipylidium caninum which rarely infects humans, usually infants and young children. The accidental ingestion of cysticercoid infected flea Ctenocephalides felis is the cause of this cestode infection in humans. Here we report the first and a rare case of adult dipylidiasis in a first-trimester pregnant woman in Ghana. She reported at the health facility for a routine antenatal check-up with apparently no symptoms or signs of the infection at the time of the visit. Her routine stool examination revealed a single egg packet of Dipylidium caninum and was treated with a single dose of praziquantel. It is important for pathologists and laboratory technicians to be aware of the emergence of human dipylidiasis in Ghana. A conscious effort should be aimed at the creation of awareness among pet owners and the general population of the public health importance of zoonotic parasites that infect pets and domestic animals

Fibroblast Growth Factor–21 ameliorates hepatic encephalopathy by activating the STAT3-SOCS3 pathway to inhibit activated hepatic stellate cells

Neurological dysfunction, one of the consequences of acute liver failure (ALF), and also referred to as hepatic encephalopathy (HE), contributes to mortality posing challenges for clinical management. FGF21 has been implicated in the inhibition of cognitive decline and fibrogenesis. However, the effects of FGF21 on the clinical and molecular presentations of HE has not been elucidated. HE was induced by fulminant hepatic failure using thioacetamide (TAA) in male C57BL/6J mice while controls were injected with saline. For two consecutive weeks, mice were treated intraperitoneally with FGF21 (3 mg/kg) while controls were treated with saline. Cognitive, neurological, and activity function scores were recorded. Serum, liver, and brain samples were taken for analysis of CCL5 and GABA by ELISA, and RT qPCR was used to measure the expressions of fibrotic and pro-inflammatory markers. We report significant improvement in both cognitive and neurological scores by FGF21 treatment after impairment by TAA. GABA and CCL5, key factors in the progression of HE were also significantly reduced in the treatment group. Furthermore, the expression of fibrotic markers such as TGFβ and Col1 were also significantly downregulated after FGF21 treatment. TNFα and IL-6 were significantly reduced in the liver while in the brain, TNFα and IL-1 were downregulated. However, both in the liver and the brain, IL-10 was significantly upregulated. FGF21 inhibits CXCR4/CCL5 activation and upregulates the production of IL-10 in the damaged liver stimulating the production pro-inflammatory cytokines and apoptosis of hepatic stellate cells through the STAT3-SOCS3 pathway terminating the underlying fibrosis in HE

Insecticide resistance status of Aedes aegypti in Southern and Northern Ghana

Background: Outbreaks of Aedes-borne arboviral diseases are becoming rampant in Africa. In Ghana, there is no organized arboviral control programme with interventions restricted to mitigate outbreaks. Insecticide application is a crucial part of outbreak responses and future preventative control measures. Thus, knowledge of the resistance status and underlying mechanisms of Aedes populations is required to ensure optimal insecticide choices. The present study assessed the insecticide resistance status of Aedes aegypti populations from southern Ghana (Accra, Tema and Ada Foah) and northern Ghana (Navrongo) respectively. Methods: Phenotypic resistance was determined with WHO susceptibility tests using Ae. aegypti collected as larvae and reared into adults. Knockdown resistance (kdr) mutations were detected using allele-specific PCR. Synergist assays were performed with piperonyl butoxide (PBO) to investigate the possible involvement of metabolic mechanisms in resistance phenotypes. Results: Resistance to DDT was moderate to high across sites (11.3% to 75.8%) and for the pyrethroids, deltamethrin and permethrin, moderate resistance was detected (62.5% to 88.8%). The 1534C kdr and 1016I kdr alleles were common in all sites (0.65 to 1) and may be on a trajectory toward fixation. In addition, a third kdr mutant, V410L, was detected at lower frequencies (0.03 to 0.31). Pre-exposure to PBO significantly increased the susceptibility of Ae. aegypti to deltamethrin and permethrin (P<0.001). This indicates that in addition to kdr mutants, metabolic enzymes (monooxygenases) may be involved in the resistance phenotypes observed in the Ae. aegypti populations in these sites. Conclusion: Insecticide resistance underpinned by multiple mechanisms in Ae. aegypti indicates the need for surveillance to assist in developing appropriate vector control strategies for arboviral disease control in Ghana. Keywords: insecticide resistance, target-site mutations, Aedes aegypti, Piperonyl butoxide Synergist, knockdown resistance, Ghana