Predicting sediment yield on different landuse surfaces in Calabar River Catchment, Nigeria.

This study predicts sediment yield on various landuse surfaces within the Calabar River Catchment, Nigeria. Five experimental plots of 31 by 23 cm (representing urban, farm, grass, bare, and forest surfaces) were established on a convex slope series with a 20% gradient, oriented along the slope strike. Rainfall, morphological, and hydraulic stations were derived for each plot. Multiple regressions and Factor analysis were employed to analyse the collected data. The research identifies critical factors influencing sediment yield, such as rainfall amount, rainfall intensity, slope gradient, slope length, sand, silt, clay, vegetation cover, and infiltration capacity. The results (p < 0.05) indicate that slope length, sand, silt, clay, infiltration capacity, and vegetation cover significantly influence sediment yield for urban, farmland, grassland, and bare surfaces, respectively. Factor analysis revealed strong correlations between sediment yield, silt, rainfall amount, rainfall intensity, and slope gradient. Case-wise diagnostics predictions indicate sediment yields for urban, bare, farm, grass, and vegetation-covered surfaces as 14.95 kg, 33.91 kg, 28.78 kg, 33.50 kg, and 5.66 kg, respectively. The regression model, with case-wise diagnostic residual statistics and standard prediction coefficients, provides valuable insights. For example, the forest surface exhibited a minimum sediment yield of -1.413 kg/m2 with each unit decrease in forest area, emphasising the significance of vegetation cover in sediment retention. Conversely, bare surfaces showed a maximum sediment yield of 0.843 kg/m2 with each unit increase in bare surface area, highlighting their heightened vulnerability to sediment erosion. Considering the implications of these findings, the development of urban master plans that incorporate well-designed landscaping and drainage systems is crucial, particularly in high rainfall catchments like the study area. Such measures can effectively mitigate sediment yield and address the adverse effects of land use changes on different surfaces.

Helminth associated hypereosinophilia and tropical endomyocardial fibrosis (EMF) in Nigeria.

There should be a recognisable trend between the incidence of hypereosinophilia and the duration of tropical endomyocardial fibrosis (EMF), if the hypothesis, that EMF is the burnt out phase of eosinophil associated heart disease, is correct. We tested this hypothesis in a prospective study of 89 consecutive EMF cases over an 18 year period at two Nigerian locations (Ife in South West and Calabar in South East). We carefully dated the duration of EMF symptoms at first presentation and screened for hypereosinophilia (eosinophilia > or = 1500/mm3), and their causes. When no cause was identified for hypereosinophilia we gave a therapeutic trial with diethylcarbamazine to the patients. An eosinophil count > or = 1000/mm3 was recorded in 80% of 24 cases seen within 6 months; 55% of 46 cases seen 0-24 months; 54% of 18 cases seen 25-48 months and 21% of 25 cases seen more than 49 months of onset of symptoms: while the respective distribution of eosinophil count > or = 1500/mm3 for similar periods were 66, 44, 27 and 21%. This reflects a highly significant (P < 0.001) inverse relationship between hypereosinophilia and the duration of EMF and strengthens the concept that EMF (without eosinophilia) represents the late stage of eosinophilic heart disease. The localisation of endemic EMF to the low-lying tropical rain forest Zone and its predominant occurrence among rural dwellers and farmers suggest a vector borne etiologic agent. Microfilaria was the most likely cause of hypereosinophilia in the cases presented.

Thalamic pain syndrome of Dejerine-Roussy.

For the general practitioner it is extremely difficult to make the diagnosis of the thalamic pain syndrome of Dejerine-Roussy which may develop in patients who have suffered a cerebrovascular accident. Because of this inability, the syndrome is considered rare in Africa. At the Teaching Hospital of the University of Calabar, Calabar, Nigeria two cases were seen recently however. We hereby present those two cases and discuss the aetiology, clinical presentation, diagnosis and treatment. This is intended to help the general practitioner to overcome the difficulties usually experienced in diagnosis and treatment of such cases.