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This working paper presents the overall and spatial accuracy assessment of the European Space Agency (ESA) 20 m prototype land cover map for Africa for four countries: Kenya, Gabon, Ivory Coast and South Africa. This accuracy assessment was undertaken as part of the ESA-funded CrowdVal project. The results varied from 44% (for South Africa) to 91% (for Gabon). In the case of Kenya (56% overall accuracy) and South Africa, these values are largely caused by the confusion between grassland and shrubland. However, if a weighted confusion matrix is used, which diminishes the importance of the confusion between grassland and shrubs, the overall accuracy for Kenya increases to 79% and for South Africa, 75%. The overall accuracy for Ivory Coast (47%) is a result of a highly fragmented land cover, which makes it a difficult country to map with remote sensing. The exception was Gabon with a high overall accuracy of 91%, but this can be explained by the high amount of tree cover across the country, which is a relatively easy class to map.

Diarrhoea disease is the second leading cause of death amongst Nigerian children (after malaria) with a prevalence rate in Nigeria of 18.8% which is one of the worst in sub-Sahara Africa. A major contributor to childhood morbidity and mortality, causes 4 million deaths each year in under-fives with each child experiencing about 5 episodes of diarrhoea yearly. We review diarrhoea diseases in children with focus on infectious diarrhoea with the aim of looking at the progress made so far in its management and control. Diarrhoea can be classified into acute and chronic; secretory, osmotic, inflammatory or due to impaired motility; infectious and non-infectious. In developing countries, infections are the most common causes of acute watery diarrhoea in children, whereas chronic diarrhoea results from non-infectious causes like inherited metabolic disorders, sensitivity to gluten orneoplasm. Diagnosis includes a careful history from the patient, examination of stool sample and examination of faecal swab samples where stool is not available. Diarrhoea in this age group is mostly of infectious origin and can be viral, bacterial, parasitic or fungi. Treatment in this environment is primarily supportive with oral or intravenous fluid and preventive measures include domestic hygiene promotion, breast-feeding promotion, improved weaning practices, probiotic use, oral rehydration therapy with additional L-glutamine, zinc supplementation and vaccination against childhood infectious diseases like rotavirus, measles and cholera. An aluminmagnesium silicate, Smectite® has been found to be of potential benefit in the management of diarrhoea. Use of Rotavirus vaccines, probiotics and Smectite® is being advocated.

Purpose: To develop and evaluate a practical phase unwrapping method for real-time phase-contrast flow MRI using temporal and spatial continuity. Methods: Real-time phase-contrast MRI of through-plane flow was performed using highly undersampled radial FLASH with phase-sensitive reconstructions by regularized nonlinear inversion. Experiments involved flow in a phantom and the human aorta (10 healthy subjects) with and without phase wrapping for velocity encodings of 100 cm.s(-1) and 200 cm.s(-1). Phase unwrapping was performed for each individual cardiac cycle and restricted to a region of interest automatically propagated to all time frames. The algorithm exploited temporal continuity in forward and backward direction for all pixels with a "continuous" representation of blood throughout the entire cardiac cycle (inner vessel lumen). Phase inconsistencies were corrected by a comparison with values from direct spatial neighbors. The latter approach was also applied to pixels exhibiting a discontinuous signal intensity time course due to movement-induced spatial displacements (peripheral vessel zone). Results: Phantom and human flow MRI data were successfully unwrapped. When halving the velocity encoding, the velocity-to-noise ratio (VNR) increased by a factor of two. Conclusion: The proposed phase unwrapping method for real-time flow MRI allows for measurements with reduced velocity encoding and increased VNR.

Cardiac structure, function and flow are most commonly studied by ultrasound, X-ray and magnetic resonance imaging (MRI) techniques. However, cardiovascular MRI is hitherto limited to electrocardiogram (ECG)-synchronized acquisitions and therefore often results in compromised quality for patients with arrhythmias or inabilities to comply with requested protocols-especially with breath-holding. Recent advances in the development of novel real-time MRI techniques now offer dynamic imaging of the heart and major vessels with high spatial and temporal resolution, so that examinations may be performed without the need for ECG synchronization and during free breathing. This article provides an overview of technical achievements, physiological validations, preliminary patient studies and translational aspects for a future clinical scenario of cardiovascular MRI in real time.