2D Electrical Resistivity Tomography (ERT) Survey using the Multi-Electrode Gradient Array at the Bosumtwi Impact Crater, Ghana

The 10.5 km diameter Bosuntwi impact crater in Ghana is occupied by a lake of about 8.5 km in diameter. The multi-electrode gradient array has been used to carry out 2D electrical resistivity tomography (ERT) survey at different locations around the crater. The 2 m take-out cable of the ABEM LUND Resistivity Imaging System was modified to function as a 5 m take-out. 2D electrical resistivity survey was carried out along six (6) radial profiles running from the shore of the lake towards the crater rim. The least-square inversion technique was used to invert the topographically corrected data. The area extending from the lake shore towards the crater rim contains essentially three formations: the low resistivity regions from the shore of the lake towards uphill with resistivities < 64 W.m representing the lake sediments; the moderately high resistivity regions with values between 128 and 200 W.m interpreted as impact related breccias such as dikes, allochthonous or parautochthonous depending on their geometries; lastly, the model clearly differentiates the resistive basement metamorphic rocks of resistivities > 128 W.m from the lake sediments and the breccias due to their geometry and lateral extent. The ERT models allowed us to locate faults and fractures and also the thickness of the post impact lake sediments and the breccias. The results showed that the cables take-outs of the multi-core cable can be modified to suit the requirements of a particular survey thus highlighting the utility of this technique in impact cratering studies and geo-electrical imaging studies in general. Keywords: impact crater, target rock, electrical resistivity tomography (ERT), multi-electrode gradient array, roll-along techniqu

Electrical Resistivity And Induced Polarization Imaging For Refuse Dump Site

Contamination from landfills as a result of leaching from organic and inorganic waste poses a threat to the environment because, subsoil and groundwater are affected. The contamination is more serious in developing countries where waste management is inefficient. The aim of this study was to determine the extent of pollution at this site. Three profiles were surveyed: two in North-South direction and the third in Northeast-Southwest. 2D electrical resistivity and Time Domain Induced Polarization (TDIP) data sets have been acquired along the three profiles in Boadi Community. Electrical resistivity and induced polarization together with excavations were successful in mapping the extent of the leachate plume. The study demarcated clearly three main zones: the first, second and third zones indicated chargeabilities > 12.8 msec near the surface, > 6.4 msec and > 12.8 msec at the base respectively. Similarly, resistivities < 12 Ωm, 12 to 24 Ωm and >192 Ωm for the first, second and third zones respectively were delineated. The relatively lower electrical resistivity areas were thought to be due to the presence of the leachate plume and the comparatively higher chargeability zones were interpreted as duricrust. The relatively lower chargeability represents absence of polarizable materials. The study also delineated the weathered basement granodiorites showing relatively higher resistivities. These TDIP and ERT results show that the methods have been successful in mapping the landfill leachate plume. The results from the resistivity and chargeability compare very well with the excavations

Creation of Humankind and the Gender Debate: Re-reading Genesis 1:26-28 and 2:18-24 and its Implications for Christians in Kumasi society

The Kumasi society of Ghana is influenced by Christianity and the Asante culture which affects gender roles in their family life church and society Women are often subordinated to men in these gender roles due to religious and cultural reasons The traditional roles of men and women have been challenged by growing feminist movements that aim to empower women in modern times This brings up questions about the traditional patriarchal norms of Christianity in societies and the reinterpretation of sacred texts that impede gender equality Despite varying interpretations an exegetical analysis of Genesis 1 26 and 2 18-14 suggests that these texts promote gender equality Kumasi society has also made strides towards gender-based equality in contemporary times through female education single parenting wider economic roles of women and the ordination of women as priests despite the patriarchal norms of Christianity and the Asante culture Nuances of Genesis 1 26-28 and 2 18-24 endorse gender equality and must inform and guide Christians of contemporary Kumasi society in championing gender equality in family church and societ

Prospecting for Groundwater Using the Continuous Vertical Electrical Sounding Method

2-D CVES surveys using the Wenner configuration was carried out in 22 communities in the Tain District, Ghana. This was done with the objectives of assessing the subsurface geology, identify high groundwater potential zones for drilling high-yielding boreholes that could yield sustainable amount of groundwater. The collected resistivity data were converted from the apparent resistivity to 2-D modelsection using the least-square inversion algorithm with the help of Res2DInv software. The 2-D resistivity model-sections produced a high quality structural resolution leading to the demarcation of the layering of various lithological units, weathered layers and identification of important structures such as joints, fractures and faults. Quantitatively, it can be observed that all the drilled wet wells have aquifer zones between 30 m and 60 m within sandstone, siltstone and phyllite granitic environments. The result of the borehole drill logs revealed that the aquifers were within weathered and fractured zones and is in agreement with the models. The results showed that the boreholes yield within the study area varied between a minimum of 15 litres/min to a maximum 800 litres/min and the mean depth for intercepting aquifer was at about 30 m and below. The study revealed that the potential aquifer zones in the study area are mostly as a result of weathering of the overburden and fracturing of the underlying bedrock. The results suggest that the hydrogeology of the study area is highly complex since the development of groundwater is generally due to secondary porosities

Use and completion of partograph during labour is associated with a reduced incidence of birth asphyxia: a retrospective study at a peri-urban setting in Ghana

Background: Morbidity of birth asphyxia has been estimated to be 42 million disability-adjusted life years. The study sought to assess the impact of the use and completion of partograph during labour on reducing birth asphyxia at the St Anthony\u2019s Hospital, Dzodze, in the Volta Region of Ghana. Methods: A retrospective study design using a quantitative approach was adopted for the study. A simple random sampling technique was used to select a total of 200 folders of labouring women who were admitted and delivered at St Anthony\u2019s Hospital, Dzodze, between 1st May 2015 and 30th April 2016. A structured checklist, which was developed by using labour and foetal monitoring parameters based on the standards of the World Health Organization partograph usage, was used to review all the 200 existing maternal records. Results: The findings revealed that partographs were used by midwives at St Anthony\u2019s Hospital with the majority of the maternal folders fully completed. The use and completion of partograph were found to be associated with less non-asphyxiated birth outcomes. Labours which were monitored with partograph were 4.29 times less likely to result in birth asphyxia [AOR (95% CI) 4.29 (1.35\u201314.81)], and those that were monitored with a completed partograph were 5.3 times less likely to result in birth asphyxia [AOR (95% CI) 5.31 (2.011\u201316.04)]. Conclusion: Midwives used partographs during labour at St Anthony\u2019s Hospital. The use and completion of partograph were significantly associated with a reduced incidence of birth asphyxia at the hospital. Birth asphyxia could be reduced if partographs are used and completed by midwives during labour in all cases

Predictors of noncompliance to antihypertensive therapy among hypertensive patients Ghana: Application of health belief model

This study determined noncompliance to antihypertensive therapy (AHT) and its associated factors in a Ghanaian population by using the health belief model (HBM). This descriptive cross-sectional study conducted at Kintampo Municipality in Ghana recruited a total of 678 hypertensive patients. The questionnaire constituted information regarding sociodemographics, a five-Likert type HBM questionnaire, and lifestyle-related factors. The rate of noncompliance to AHT in this study was 58.6%. The mean age (SD) of the participants was 43.5 (±5.2) years and median duration of hypertension was 2 years. Overall, the five HBM constructs explained 31.7% of the variance in noncompliance to AHT with a prediction accuracy of 77.5%, after adjusting for age, gender, and duration of condition. Higher levels of perceived benefits of using medicine [aOR=0.55(0.36-0.82),p=0.0001] and cue to actions [aOR=0.59(0.38-0.90),p=0.0008] were significantly associated with reduced noncompliance while perceived susceptibility [aOR=3.05(2.20-6.25),

Zero malaria: a mirage or reality for populations of sub-Saharan Africa in health transition

The global burden of malaria continues to be a significant public health concern. Despite advances made in therapeutics for malaria, there continues to be high morbidity and mortality associated with this infectious disease. Sub-Saharan Africa continues to be the most affected by the disease, but unfortunately the region is burdened with indigent health systems. With the recent increase in lifestyle diseases, the region is currently in a health transition, complicating the situation by posing a double challenge to the already ailing health sector. In answer to the continuous challenge of malaria, the African Union has started a "zero malaria starts with me” campaign that seeks to personalize malaria prevention and bring it down to the grass-root level. This review discusses the contribution of sub-Saharan Africa, whose population is in a health transition, to malaria elimination. In addition, the review explores the challenges that health systems in these countries face, that may hinder the attainment of a zero-malaria goal

Développement de méthodes LC-MS pour l'identification des triglycérides dans les huiles de graines de résineux

Cette thèse a consisté à développer une nouvelle stratégie analytique en utilisant le couplage chromatographie liquide - spectrométrie de masse (LC-MSn) afin d’identifier dans les huiles et corps gras, les triglycérides (TAGs) et leur régio-spécificité. Cette méthodologie analytique générale a été appliquée à 8 huiles de graine de résineux en particulier, à l’huile de pignon de Pinus Koraiensis car ses TAGs sont constitués d’acides gras, possédant une double liaison en position Δ5, non-méthylène alternée, susceptibles de jouer un rôle anti-cholestérol chez l’homme.La thèse se décompose en quatre chapitres: les deux premiers, bibliographiques, traitent respectivement de la taxonomie des 8 résineux étudiés, de la composition en acide gras (AG) de leur graine et des techniques analytiques déjà décrites pour caractériser les TAGs. Le troisième chapitre, expérimental, est dédié au développement de nouvelles stratégies analytiques NARP-LC-MSn mises en place pour identifier les TAGs présents dans les huiles et plus particulièrement à l’huile de pignon de Pinus Koraiensis. Grâce à l’ajout post colonne de sel d’argent, il a été possible de déterminer de manière non ambigüe la structure de tous les TAGs d’un lipide, même ceux présents en faible quantité, par Ag+-NARP-LC-MS mais aussi de déterminer la structure de chaque AG constitutif d’un TAG par fragmentation de l’adduit moléculaire par Ag+-NARP-LC-MS2. Le problème de la distinction des TAGs ayant la même masse moléculaire, les mêmes longueurs de chaine mais des positions de double liaisons différentes, a été résolu en développant une méthode d’identification des TAGs à partir des lois de rétention chromatographiques qui relient linéairement le logarithme du facteur de rétention de chaque TAG soit au nombre total de carbone soit au nombre total de double liaisons. Cette étude a permis d’identifier 22 nouveaux TAGs parmi un nombre total de 58 TAGs caractérisés. Elle a amené la preuve que le résidu AG saturé à 17 atomes de carbone est ramifié et non linéaire. Elle a mis en évidence la présence de trois AGs constitutifs qui n’ont jamais été décrit: 19:1, 19:2 et 24:0 dans l’huile de pignon de Pinus Koraiensis. Le quatrième chapitre porte sur le développement de trois méthodes de détermination de la régiospécificité des TAGs, grâce à la seule SM: (1) une méthode Ag+-NARP-LC-ESI-MS2 utilisant les rapports des ions diglycériques des TAGs. Il en ressort que cette méthode n’est pas assez fiable pour déterminer la structure des TAGs. (2) la seconde méthode fait appel à des expériences MS4/ MS5 sur les adduits argent des TAGs. Elle s’avère pertinente à condition d’avoir à disposition les couples de TAGs standards. (3) enfin une troisième méthode, utilisant la MS2, s’appuie sur le principe de la méthode de dissociation compétitive d’une paire [TAGref – Li -TAG]+. En utilisant la méthode des ajouts dosés il est montré qu’elle ne nécessite que de la disponibilité d’un seul des deux TAGs stéréoisomères comme standard.Ces méthodes originales ont permis, malgré leurs limites respectives de caractériser la régiospécificité d’un certain nombre de TAGs présents dans l’huile de graine de Pinus Koraiensis.This thesis consisted of developing a new analytical strategy using liquid chromatography coupled with mass spectrometry (LC-MSn) to identify in oils and fats, triglycerides (TAGs) and their regio-specificity. The general analytical methodology was applied to 8 conifers seed oils, in particular, the seed oil of Pinus koraiensis. These conifer seed oils differ from common edible vegetable oils by having a series of unusual polyunsaturated fatty acids (UPIFA) with a polymethylene-interrupted (PMI) double bond system and a double bond at the 5 position which may have anti-cholesterol properties. This thesis is composed of four chapters: the two first chapters, literature review, are devoted respectively to TAGs of the 8 resinous seed oils studied and analytical techniques already used. The third chapter is dedicated to the development of a new analytical strategy combining HPLC with mass spectrometry method to identify TAGs in Pinus Koraiensis seed oil. Thanks to post column addition of silver salt, it was possible to determine the TAGs present by Ag+-NARP-LC-MS and also the fatty acids composition of the TAGs by Ag+-NARP-LC-MS2. Concerning the distinction between TAGs with the same mass, same chain length but differing positions of double bond on fatty acid chain, it was determined by chromatographic retention rules which link linearly the logarithm of retention factor of each TAG to the total carbon number or the total number of double bonds. This study has identified 22 new TAGs from a total of 58 TAGs characterized. It confirmed the knowledge that the saturated fatty acid with 17 carbon atoms is branched, not linear. It highlighted the presence of three constituent fatty acids that have never been described: 19:1, 19:2 and 24:0 in the seed oil of Pinus koraiensis. The last experimental part is devoted to the regiospecificity determination of TAGs. Three methodologies were developed. The first one used the ratios of diacylglycerol ions of TAGs but was not reliable enough. The second method used the LC-MS4 experiments (It is relevant if they have available couples of TAG standards). Finally, a third method, using MS2, based on the principle of the method of competitive dissociation of a pair [TAGref - Li-TAG] +. Using the method of standard additions it has been shown that it requires the availability of one of the two stereoisomers TAGs as a standard.These methods provide a significantly different approach to regioisomer characterization of TAGs and overcome most of the shortcomings of existing methodologies

L'impact du cratère du lac Bosumtwi : l'utilisation de la tomographie de la résistivité électrique (TRE) pour tracer la carte géométrique de la paroi internet du cr&tère et de l'impact associé à la structure

Des mesures de résistivité électrique et des campagnes d’observations géologiques ont été menées pour cartographier le contact sédiment/roche basale ainsi que les structures d’impact associées au cratère d’impact Bosumtwi datant de 1,07 millions d’années. Le cratère de 10,5 km de diamètre s’est formé dans des roches métamorphiques du Précambrien (2,1 à 2,2 milliard d’années), d’origine sédimentaire et volcanique. Il est actuellement rempli par le lac Bosumtwi de 8,5 km de diamètre. Ce cratère est la source des tektites et microtektites dispersées jusqu’en Côte d’Ivoire et au large des côtes ouest africaine. La campagne de mesures éophysiques consiste en 16 tomographies de résistivité électrique effectuées radialement des rives du lac vers les bords du cratère d’impact. Chaque profil utilise un système d’acquisition multi – électrodes avec une distance minimum entre les électrodes de 5 m. Les données ont été corrigées des effets topographiques et inversées en utilisant le programme commercial d’inversion Res2DInv, avec la norme L1 considérée plus robuste. La zone comprise entre les rives du lac et le bord externe du cratère de divise en trois formations géologiques principales. Les régions de faibles résistivités ( 128 .m) représentent les roches métamorphiques sous-jacentes, d’origine volcanique ou sédimentaire. Les profils de résistivités permettent de retrouver la géométrie et l’extension latérale de ces trois types de roches. Une correspondance directe entre la lithologie observée en surface et les structures mises en évidence par les mesures de résistivité électrique dans le sous-sol est observée à Dwamam au Sud-Est dulac. À Dwamam, les sédiments sont environ à 200 m de la rive du lac et s’étendent environ sur 400 m vers les les bords du cratère, à la différence des autres zones où ont pu être cartographiés les sédiments. La topographie du contact sédiment/roche basale présente une direction particulière NE-SO avec un pendage variant entre 16 degrés au NE et 36 degrés au SO. Une majorité de fractures ont été remarquées dans le SO, remplies par des clasts et des brèches d’impacts. Les failles sont surtout présentent à l’Ouest du lac. En moyenne elles présentent un pendage variant entre 60o à l’Est et 80 degrés à l’Ouest du cratère. Des analyses statistiques ont été effectuées sur les directions et les pendages des failles selon les loi de von Mises et Fisher. Elles démontrent que les failles s’alignent préférentiellement le long de deux directions principales. L’analyse cumulée de la surface de contact sédiment/roche, des failles et de la localisation du champ de dispersion des tektites indique que le bolide d’environ 0,8 à 1 km de diamètre responsable du cratère est arrivé du NE. Les résultats démontrent que les panneaux de résistivité électrique fournissent des informations utiles pour l’étude des cratères d’impact.Electrical resistivity tomography (ERT) and geological field surveys have been used to map the sediment/bedrock contact and impact related structures of the 1.07 Myr old Bosumtwi impact crater. The 10.5 km complex crater excavated in 2.1–2.2 Gyr Precambrian metasedimentary and metavolcanic rocks is filled by the 8.5 km Lake Bosumtwi. It is the source crater of the tektites and microtektites of the Ivory Coast strewn field. Electrical resistivity survey was carried out sixteen (16) profiles running from the shore of the lake towards the rim of the crater. The multi-electrode gradient array method with minimum electrode separation of 5 m was used. The data were corrected for topography and inverted using the L1–norm (robust inversion) techniqueof the Res2DInv software. The area extending from the lake shore towards the crater rim contains essentially three formations. The low resistivity regions ( 128 .m) fromthe lake sediments and the breccias due to their geometry and lateral extent. Also observed was a direct correspondence between the lithology on the surface and the subsurface resistivity structures at Dwamam in the southeast section of the lake. At Dwamam, the sediments were about 200 m away from the shore and stretch about 400 m towards the crater rim unlike in other areas where the sediments were mapped from the shore. The gradient of the sediments/bedrock contact showsa symmetry in the NE–SW direction and dips between the lowest of 16 degrees in the NE to the highest 36 degrees in the SW. Majority of the fractures marked were in the southwest and were filled with clasts or impact breccia matrix. The faults were mostly delineated in the west. Averagely, the dips of the faults are about 60 degrees and 80 degrees for the east and west sections of the crater respectively. The dips of the faults were statistically treated using the von Mises and Fisher statistics, it was found that the faults have a preferred direction and it is possible to determine at least two different orientations. Theanalysis of the results of the sediments/bedrock surface and the faults combined with the location of the tektite strewn field indicate that the about 0.8–1 km bolide that created the complex crater came from the NE. The findings have shown that the ERT is efficient and a useful tool in impact cratering science research

Bosumtwi impact crater : use of electrical resistivity tomography (ERT) to map the geometry of the inner wall of the crater and the impact related structures

Electrical resistivity tomography (ERT) and geological field surveys have been used to map the sediment/bedrock contact and impact related structures of the 1.07 Myr old Bosumtwi impact crater. The 10.5 km complex crater excavated in 2.1–2.2 Gyr Precambrian metasedimentary and metavolcanic rocks is filled by the 8.5 km Lake Bosumtwi. It is the source crater of the tektites and microtektites of the Ivory Coast strewn field. Electrical resistivity survey was carried out sixteen (16) profiles running from the shore of the lake towards the rim of the crater. The multi-electrode gradient array method with minimum electrode separation of 5 m was used. The data were corrected for topography and inverted using the L1–norm (robust inversion) techniqueof the Res2DInv software. The area extending from the lake shore towards the crater rim contains essentially three formations. The low resistivity regions ( 128 .m) fromthe lake sediments and the breccias due to their geometry and lateral extent. Also observed was a direct correspondence between the lithology on the surface and the subsurface resistivity structures at Dwamam in the southeast section of the lake. At Dwamam, the sediments were about 200 m away from the shore and stretch about 400 m towards the crater rim unlike in other areas where the sediments were mapped from the shore. The gradient of the sediments/bedrock contact showsa symmetry in the NE–SW direction and dips between the lowest of 16 degrees in the NE to the highest 36 degrees in the SW. Majority of the fractures marked were in the southwest and were filled with clasts or impact breccia matrix. The faults were mostly delineated in the west. Averagely, the dips of the faults are about 60 degrees and 80 degrees for the east and west sections of the crater respectively. The dips of the faults were statistically treated using the von Mises and Fisher statistics, it was found that the faults have a preferred direction and it is possible to determine at least two different orientations. Theanalysis of the results of the sediments/bedrock surface and the faults combined with the location of the tektite strewn field indicate that the about 0.8–1 km bolide that created the complex crater came from the NE. The findings have shown that the ERT is efficient and a useful tool in impact cratering science research.Des mesures de résistivité électrique et des campagnes d’observations géologiques ont été menées pour cartographier le contact sédiment/roche basale ainsi que les structures d’impact associées au cratère d’impact Bosumtwi datant de 1,07 millions d’années. Le cratère de 10,5 km de diamètre s’est formé dans des roches métamorphiques du Précambrien (2,1 à 2,2 milliard d’années), d’origine sédimentaire et volcanique. Il est actuellement rempli par le lac Bosumtwi de 8,5 km de diamètre. Ce cratère est la source des tektites et microtektites dispersées jusqu’en Côte d’Ivoire et au large des côtes ouest africaine. La campagne de mesures éophysiques consiste en 16 tomographies de résistivité électrique effectuées radialement des rives du lac vers les bords du cratère d’impact. Chaque profil utilise un système d’acquisition multi – électrodes avec une distance minimum entre les électrodes de 5 m. Les données ont été corrigées des effets topographiques et inversées en utilisant le programme commercial d’inversion Res2DInv, avec la norme L1 considérée plus robuste. La zone comprise entre les rives du lac et le bord externe du cratère de divise en trois formations géologiques principales. Les régions de faibles résistivités ( 128 .m) représentent les roches métamorphiques sous-jacentes, d’origine volcanique ou sédimentaire. Les profils de résistivités permettent de retrouver la géométrie et l’extension latérale de ces trois types de roches. Une correspondance directe entre la lithologie observée en surface et les structures mises en évidence par les mesures de résistivité électrique dans le sous-sol est observée à Dwamam au Sud-Est dulac. À Dwamam, les sédiments sont environ à 200 m de la rive du lac et s’étendent environ sur 400 m vers les les bords du cratère, à la différence des autres zones où ont pu être cartographiés les sédiments. La topographie du contact sédiment/roche basale présente une direction particulière NE-SO avec un pendage variant entre 16 degrés au NE et 36 degrés au SO. Une majorité de fractures ont été remarquées dans le SO, remplies par des clasts et des brèches d’impacts. Les failles sont surtout présentent à l’Ouest du lac. En moyenne elles présentent un pendage variant entre 60o à l’Est et 80 degrés à l’Ouest du cratère. Des analyses statistiques ont été effectuées sur les directions et les pendages des failles selon les loi de von Mises et Fisher. Elles démontrent que les failles s’alignent préférentiellement le long de deux directions principales. L’analyse cumulée de la surface de contact sédiment/roche, des failles et de la localisation du champ de dispersion des tektites indique que le bolide d’environ 0,8 à 1 km de diamètre responsable du cratère est arrivé du NE. Les résultats démontrent que les panneaux de résistivité électrique fournissent des informations utiles pour l’étude des cratères d’impact