Solving Minimum Cost Multi-Commodity Network Flow Problem Using Lexicographic Goal Programming Approach

In an urban transport system, a dysfunction often occurred as demand for transportation infrastructure exceeds available supply. The result includes traffic congestion, higher travel time and cost, higher emission of harmful gases and general reduction in quality of life. In this research, an attempt was made to minimize travel time on three urban road segments using Lexicographic Goal Programming. The positive and negative deviations from the goals were minimized. A minimum cost multi-commodity network flow problem with multiple objectives was successfully modelled using LINDO 6.1. The modelling technique provided a solution that effectively minimized travel time by 50%

Spatial Analysis of Accident Spots Using Weighted Severity Index (WSI) and Density-Based Clustering Algorithm

This study is based on evaluation of various factors that cause road accidents in Lagos Metropolis. Fourteen (14) factors/drivers were identified which tend to influence an occurrence of accident on Lagos roads. In order to study the pattern of accidents in the Metropolis, several different spatial and non-spatial datasets were collected, processed and analysed. Weighted Severity Index (WSI) was created based on these factors/drivers. Also, Density-based Clustering for Traffic Accident Risk (DBCTAR) was carried out to assist in ascertaining the distribution of Black Spots Severity (BSS). Results obtained include: shortestpath analysis, service area analysis, accident spot severity and vulnerability level across the Metropolis based on the Weighted Severity Index (WSI). The study reveals that, accidents are not always caused as a result of bad roads but by the smoothness of roads such as expressway with accident spots distance band of 300m-500m and 3.6% of the accidents is as a result of pedestrians avoiding the use of pedestrian bridges/aid even when they are available.Key Words: Accident Spots, Weighted Severity Index (WSI), Vulnerability, Pedestrians, Transportation

Empirically Determined Passenger Ferry Navigable Routes within Lagos Lagoon

Hydrographic surveys define shorelines and depths of lakes, streams, oceans, reservoirs, and other bodies of water. Sea surveying is associated with port and offshore industries and the marine environment, including measurements and marine investigations made by ship-borne personnel. In addition, accurate measurement and modelling of hydrographic information is important to control waterways boat services with existing roadway transportation services. This paper attempts an empirical analysis of hydrographic data to simulate waterway navigable route within Lagos Lagoon with a minimum under-keel clearance that must be maintained by vessel transiting a port as well as berthing. The field investigation was conducted between September 2015 and March 2016 to determine river bed topography with the deployment of DGPS receivers, Single beam SDE 28S echo sounder, speed boat, tidal observation and reduction. Hypack 2008 and Arc GIS software was used for data sorting, extraction and processing. It was observed that depth within the project area ranges between 0.0m to 14.82m when referred to the Lagos datum. Furthermore, waterway navigable chart was developed based on prevailing river bed topography along the study corridors as well as passenger ferry draught constraint. From this study, derived depths were analysed in form of graphs and charts that provides a suitable framework to support ferry transportation services within Lagos Lagoon as a complimentary mode to the dominantly depended road transportation services. Therefore, periodic hydrographic survey of the navigable routes is recommended specifically to identify possible channel accretion.Keywords: Navigable routes, hydrographic information, empirical analysis, under-keel clearance, river bed, topograph

Gastrointestinal stromal tumours at the university of nigeriateaching hospital Enugu, Nigeria: an immunohistochemical study of gitmesenchymal tumours

Mesenchymal tumours of the gastrointestinal tract (GIT) are uncommon. Recent progress in the understanding  of the biology and origin of these tumours has led to their reclassification. A new subclass designated Gastrointestinal Stromal Tumours (GIST) is diagnosed based on the presence of a mutational over expression of c-kit protein that is thought to be critical in the pathogenesis of these tumours.This newclass of tumoursmay form the majority of gastrointestinal mesenchymal tumours. Even though the diagnosis of GIST is mainly based on positive staining with CD117, a minority of tumours with histological characteristics of GIST are CD117 negative and are classified asCD117 negativeGIST. In this first reviewof mesenchymalGITtumours fromNigeria,we present 11 cases ofmesenchymal tumours of the gastrointestinal tract seen within a six-year period at our centre. Immunohistochemistry was performed on 7 of themin which histological appearances suggested GIST. Only two cases had all the criteria defined in the consensus conference on the diagnosis ofGIST. Our findings, albeit in a very small sample, contrastswith what obtains in developed countries in the proportion of GIT mesenchymal tumours that are truly GIST. This raises a question to be answered on the true nature and proportion of gastrointestinal strumal tumours among GITtumours inNigerian patients.Keywords: Gastrointestinal, Stromal, Mesenchymal, Immunohistochemistry

Visualisation of Uncertainty in 30m Resolution Global Digital Elevation Models: SRTM v3.0 and ASTER v2

Geospatial visualisation presents us with innovative techniques of assessing uncertainty in digital elevation datasets. It gives the viewer immediate feedback on potential problems and heightens understanding of effects not easily appreciated when dealing with numerical statistics only. This study evaluated the performance of 30-metre resolution SRTM version 3.0 and ASTER GDEM version 2 over Lagos, Nigeria. Both datasets were examined by direct comparison with 176 highly accurate Ground Control Points (GCPs) coordinated by GPS (Global Positioning System) observation. The basis of comparison was on the elevation differences between the Digital Elevation Models (DEMs) and the GCPs at coincident points. The performance of both DEMs was visualised in 2D and 3D space by comparing pixel values and surface models. In the assessment, the absolute vertical accuracies of SRTM v3.0 and ASTER v2 are 4.23m and 28.73m respectively. The accuracy of SRTM for the study site proved to be higher than the value of 16m presented in the original SRTM requirement specification. ASTER did not meet up with its 17m overall accuracy specification.KEYWORDS: Uncertainty, Visualisation, Digital Elevation Model, SRTM, ASTER

Oncocytic Schneiderian Papilloma Occurring In a Young Nigerian Male: A Case Report

Oncocytic Schneiderian papilloma is one of the three morphologically separate tumors that arise from the Schneiderian membrane (the others are fungi form papilloma and inverted papilloma). It is quite rare in our environment. We report a case of Oncocytic Schneiderian papilloma arising from the right maxillary sinus and extending to the ipsilateral nasal region in a 26year old Nigerian male. The growth was present for a period of 5 months before his presentation on 18-10-2005 and recurred again nine months later after excision. Both excised tissues were confirmed by histology to be Oncocytic Schneiderian papilloma, with no evidence of malignancy after a rigorous search.Le papillome schneidérien oncocytique est une des trois tumeurs morphologiquement indépendante qui se soulève de la membrane schneidérien (l y a d\'autres comme ; le papillome creux et le papillome fongueux) c\'est rare chez nous. Nous aimerons souligner un cas de papillome schneidérien oncocytique qui se soulève du coté droit du sinus maxillaire et porte plus loin jusqu a la région nasale d\'un jeune nigérian de 26 ans. La grosseur était présente pendant cinq mois et puis après avoir été excisé grâce a une intervention chirurgicale 18-10-2005, elle a réapparu neuf mois plus tard. On a pu identifier, a travers l\'histologie, que les deux tissus excisés étaient papillome schneidérien oncocytique, sans aucun signe de malignité au bout d\'une recherche rigoureuse. Keywords: Oncocytic Schneiderian papilloma Annals of African Medicine Vol. 7 (2) 2008: pp. 91-9

Associations Between Healthcare Utilization Factors and Diabetic Retinopathy Among Adult African Americans

African Americans are disproportionately affected by diabetes mellitus (DM) and complications that include diabetic retinopathy and its disease and socioeconomic burdens. This study examined the relationships between diabetic retinopathy and health care utilization factors, such as gender, DM comorbidities of hypertension and hyperlipidemia, and health care access, among sampled African Americans with DM in the United States. The Andersen health care utilization model was the framework for the study. In this correlational cross-sectional study, data from the 2011-2016 National Health and Nutrition Examination Survey datasets were analyzed. Results of complex samples logistic regression showed that there were no significant associations between diabetic retinopathy and DM comorbidities of hypertension and hyperlipidemia, gender, and health care access, after controlling for hemoglobin A1C level, urine albumin-to-creatinine ratio (UACR), marital status, education level, and annual household income. UACR, annual household income, and adult education level were significantly associated with diabetic retinopathy (p \u3c.005). Researchers might use findings from this study for further studies to establish cause-and-effect relationships between diabetic retinopathy and the related health utilization factors in this population. Positive social change might be effected by using results from the study in planning and developing effective public health interventions targeting specific African American populations, which might result in a reduction of the associated physical and socioeconomic burdens on these populations

An Assessment of the Emerging Networks of Support for Street Children in Nigeria

Nigeria, being asignatory to the Convention on the Rights of the Child(UNCRC, 1989) promulgated the Child Rights Act 2003, which aimed atameliorating the condition of street children in Nigeria. In line with this,there are emerging networks of support for street children. The extent towhich these support networks are fulfilling their mission mandates is not yet known. Hence, this paper attempts to bridge this gap by focusing on the available networks of support for these children, who were mainly on their own, and often left to face the horrors of street life without recourse to their significant others. Both quantitative and qualitative techniques were employed to collect primary data for the study. Study findings showed that Children ‘of’ the street enjoyed more supports from community members in Kaduna (56.6%) and Port Harcourt (59.0%) than in Lagos (19.0%). Although, few NGOs now work with the street children, their impacts are yet to be felt because of lack of requisite resources. The government through the Social Welfare Department also provides some assistance to street children; their programmes were not attractive enough to the children. On the whole, the children’s ranking of the ‘support providers’ shows that the support provided by the homeless adults on the street is most preferred (μ=3.26) while the government agencies were least on this ranking scale (μ=1.78).The study concluded that, despite the global shift from eradication of street children to providing support for them right on the streets, this paradigm shift has very weak roots in Nigeria. Hence, children ‘of’ the street are still socially excluded in Nigeria. This has serious implication for the future of the country since it could lead to the proliferation of street gangs who are often involved in various crimes and ready instruments of violence. Increase in the population of street children and possibly street gangs could become serious economic burden to the nation. It is therefore important to attract support to the children ‘of’ the street in order to reverse this problem

Malignant Struma Ovarii: Case Report and a Review of the Literature

Struma ovarii is a rare tumor. Malignant change in this tumour is even rarer. While clinical presentation is protean, a preoperative diagnosis is equally difficult. Diagnosis is confirmed by histology. Treatment ofmalignant struma ovarii is by surgical resection of the tumor or total abdominal hysterectomy and bilateral salpingo-oophorectomy. A total thyroidectomy allows radioactive iodine ablation and the use of thyroglobulin as marker to monitor recurrence. However due to rarity of the disease, standard treatment is still controversial. We present a case of malignant struma ovarii, followed up for five years after treatment, and a review of the literature on the disease. The patient was treated with surgery and radiation. She is still free of disease after 5 years.Key Words: Malignant Struma Ovarii, Ovarian Teratoma, Papillary Thyroid Carcinom