Determination of surface fluxes using a Bowen ratio system

Components of the surface fluxes of the energy balance equation were determined using a Campbell Bowen ratio system. The fluxes are obtained by the energy balance Bowen ratio technique, a gradient method that uses vertical gradients of temperature and vapour pressure in combination with point measurements of net radiation and soil heat flow from two sets of soil sensors. The Bowen ratio was measured as the ratio of air temperature and vapour pressure gradients between two fixed heights within 6 m of the surface. Net radiation (Rn) was measured using net radiometers. Soil heat flux (Qg) was measured with ground heat flux plates and the change in energy storage of the layer of soil above the heat flux plates was computed using direct measurements of soil temperature and moisture content. Measurements made every 20 min are stored in the Campbell data logger. Results show most of the net radiation is converted to latent heat when there are more water available for evaporation. Estimates of sensible and latent heat flux have an accuracy of ± 10% of the measured value

Rural Origin and Exposure Drives Ghanaian Midwives Reported Future Practice

A primary cause of Ghana’s higher than global average maternal mortality rate is limited access to maternal care in rural areas. To date, few studies have examined how rural background/training of midwives impacts their future willingness to work in remote areas. The purpose of this paper is to describe the relationship between Ghanaian student midwife place of origin and rural training on their willingness to choose a future rural practice location. A cross-sectional computer-based survey was completed by 238 final year Ghanaian midwifery students from two public midwifery training schools located in urban Ghana between October and December 2009. The relationship between rural exposure and willingness to work in rural Ghana was analyzed using independent t-test, chi-square, and bivariate logistic regression. Participants who experienced a rural rotation (OR: 1.51, 95% CI: 0.71, 3.22) and those born in a rural area (OR: 2.24, 95% CI: 0.74, 6.75) resulted in greater odds ratio to choose rural practice following graduation. This study indicates an association between midwifery students’ place of origin and training and their willingness to practice in a rural area after graduation. (Afr J Reprod Health 2014; 18[3]: 95-100)Keywords: Midwifery, Ghana, human resources for health, maldistribution, rural practice, rural incentive

Compression force variability in mammography in Ghana – a baseline study

Introduction: Breast compression during mammographic examinations improves image quality and patient management. Several studies have been conducted to assess compression force variability among practitioners in order to establish compression guidelines. However, no such study has been conducted in Ghana. This study aims to investigate the compression force variability in mammography in Ghana. Methods: This retrospective study used data gathered from 1071 screening and diagnostic mammography patients from January, 2018–December, 2019. Data were gathered by seven radiographers at three centers. Compression force, breast thickness and practitioners' years of work experience were recorded. Compression force variability among practitioners and the correlation between compression force and breast thickness were investigated. Results: Mean compression force values recorded for craniocaudal (CC) (17.2 daN) and mediolateral oblique (MLO) (18.2 daN), were within the recommended values used by western countries. Most of the mammograms performed – 80% – were within the National Health Service Breast Screening Programme (NHSBSP) range. However, 65% were above the Norwegian Breast Cancer Screening Programme (NBCSP) range. Compression forces varied significantly (p = 0.0001) among practitioners. Compression forces increased significantly (p = 0.0001) with the years of work experience. A weak negative correlation (r = −0.144) and a weak positive correlation (r = 0.142) were established between compression force and breast thickness for CC and MLO projections respectively. Conclusion: This initial study confirmed that although wide variations in compression force exist among practitioners in Ghana, most practitioners used compression forces broadly within the range set by the NHSBSP. As no national guidelines for compression force currently exist in Ghana, provision of these may help to reduce the range of variations recorded. Implications for practice: Confirmation of variations in compression will guide future practice to minimize image quality disparities and improve quality of care

Pottasium-Argon dating of Ghanaian rocks

No Abstract

Pattasium-argon ages of two granitoids Northwest of Kumasi, Ghana

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Conventional K-Ar and 40AR/39AR ages of the miocene submarine rocks of the Cape Vrede Islands

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Potassiium-Argon radiometric dates of the Mid-Atlantic ocean floor

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Potassium-argon ages of gneisses from the basin granitoid in South-Eastern Ghana

Biotite and hornblende from gneiss samples from the basin granitoid in South-eastern Ghana were separated and analyzed for potassiumargon (K / Ar) ages. The results indicated that the gneisses have average biotite and hornblende ages of 1942 ± 11 Ma and 2044 ± 17 Ma, respectively. The highest single hornblende age of 2092 Ma was recorded for the amphibolite gneiss, which is a protolith of tholeiitic basalt. These ages fall within the main phase of the Eburnean thermo-tectonic event. The defined ages correspond to the metamorphic event, and are expectedly lower than the average ages of 2270 Ma (Pb/Pb), 2116 Ma (U/Pb), 2216 Ma (Rb/Sr, WR Isochron), and 2240-2290 Ma (Sm/Nd, Model) determined for the basin granitoid in other parts of Ghana and the reported Birimian age (2000- 2300 Ma). This confirms that the basin granitoid was derived from older basement rocks, and that its emplacement was contemporaneous with the activities that resulted in the emplacement of the Birimian volcanic rocks and sediments. A period of 70 to 250 Ma separates the period of emplacement of the basin granitoid and subsequent metamorphic activities. However, the period of metamorphism of the basin granitoid (1922-2045 Ma) was contemporaneous with the intrusion by the Nsawam microgranite (1996 ± 43 Ma), and that of the Tarkwaian sediments by the K-rich granitoid (1968 ± 49 Ma). Ghana Journal of Science Vol. 45, 2005: 27-3