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Yaoundé, Cameroon

Wanji S.,University of Buea | Wanji S.,Research Foundation for Tropical Diseases and Environment | Kengne-Ouafo J.A.,University of Buea | Kengne-Ouafo J.A.,Research Foundation for Tropical Diseases and Environment | And 18 more authors.
Parasites and Vectors | Year: 2015

Background: Community-Directed Treatment with Ivermectin (CDTI) is the main strategy adopted by the African Programme for Onchocerciasis control (APOC). Recent reports from onchocerciasis endemic areas of savannah zones have demonstrated the feasibility of disease elimination through CDTI. Such information is lacking in rain forest zones. In this study, we investigated the parasitological and entomological indices of onchocerciasis transmission in three drainage basins in the rain forest area of Cameroon [after over a decade of CDTI]. River basins differed in terms of river number and their flow rates; and were characterized by high pre-control prevalence rates (60-98%). Methods: Nodule palpation and skin snipping were carried out in the study communities to determine the nodule rates, microfilarial prevalences and intensity. Simulium flies were caught at capture points and dissected to determine the biting, parous, infection and infective rates and the transmission potential. Results: The highest mean microfilaria (mf) prevalence was recorded in the Meme (52.7%), followed by Mungo (41.0%) and Manyu drainage basin (33.0%). The same trend was seen with nodule prevalence between the drainage basins. Twenty-three (23/39) communities (among which 13 in the Meme) still had mf prevalence above 40%. All the communities surveyed had community microfilarial loads (CMFL) below 10 mf/skin snip (ss). The infection was more intense in the Mungo and Meme. The intensity of infection was still high in younger individuals and children less than 10 years of age. Transmission potentials as high as 1211.7 infective larvae/person/month were found in some of the study communities. Entomological indices followed the same trend as the parasitological indices in the three river basins with the Meme having the highest values. Conclusion: When compared with pre-control data, results of the present study show that after over a decade of CDTI, the burden of onchocerciasis has reduced. However, transmission is still going on in this study site where loiasis and onchocerciasis are co-endemic and where ecological factors strongly favour the onchocerciasis transmission. The possible reasons for this persistent and differential transmission despite over a decade of control efforts using ivermectin are discussed. © 2015 Wanji et al.; licensee BioMed Central.

Mokpidie D.,University of Bangui | Lazar G.,University of Bacau | Faciu E.,University of Bacau | Mossoa L.,University of Bangui | And 3 more authors.
Environmental Engineering and Management Journal | Year: 2014

The paper presents the preliminary results obtained using the Geographic information System (GIS) techniques in the study of vegetation dynamics in a peri-urban area, having as case study the forest in a region of southwestern Central African Republic. The study area concerns a zone located between 4° 00' - 4° 30' North latitude and 18° 15' - 18° 30' East longitude, having a total surface of 156,531 ha, from which 88,547 ha is exploitable area. The satellite images (Landsat TM 1984 images, captured during the dry season, March, and 2008, also captured during the dry season, April), aerial photographs and other support information from 1984 and 2008 were used to realize the two soil occupation maps, separated by 24 years. The results show that the area occupied by forest decreased during the analyzed period by more than 25%, from 148,905 ha to 109,246 ha; the data also indicate a significant increase in the proportion of the degraded forest, from 7,203 ha to 39,329 ha. Even if at this stage the tool does not allow very precise identification of the causes that led to the reduction of area occupied by forest and the decrease of its quality, the database can be completed and used as a policymaker tool. © 2014, (publisher). All rights reserved.

Mainsah E.N.,University of Buea | Ndifon P.T.,University of Yaounde1 | Nfor E.N.,University of Buea | Njapba J.N.,University of Buea
Bulletin of the Chemical Society of Ethiopia | Year: 2013

A new ligand, (1H-pyrrol-2-yl)isonicotinoylhydrazone (Pyr-inh) and its metal complexes have been synthesised and characterized by elemental analyses, IR, 1H and 13C-NMR, UV-Vis spectra, molar conductance, and thermogravimetry-differential thermal analysis (TG-DTA). From the results obtained, the structure of the complexes are of general formula [M(Pyr-inh) 2Cl2].xH2O for M = Co(II), and Zn(II) and [M(Pyrinh) 2(H2O)2]Cl2 for Cu(II). The thermal behaviour of these complexes showed the loss of lattice water in the first step followed by decomposition of the ligand in subsequent steps. The ligand and its transition metal complexes were studied for their in vitro antibacterial activity against ten pathogenic bacterial strains. The data obtained revealed that the ligand was active against Morganella morganii and Escherichia coli, the Co(II) complex active against Klebsiella oxytoca, the Cu(II) complex showed significant activity against five out of the ten bacterial strains and the Zn(II) complex was active against all the pathogenic bacterial strains investigated. © 2013 Chemical Society of Ethiopia.

Kenfack C.,University of Yaounde I | Kenfack C.,University of Yaounde1 | Kenfack C.,University of Quebec at Montreal
ICSOFT 2013 - Proceedings of the 8th International Joint Conference on Software Technologies | Year: 2013

This paper presents the implementation of an intelligent tutoring system (ITS) using the Jade agents intermediation system (AIS) for community of practice to support knowledge emergence and sharing in collaborative learning situation The key component is the community of practices model which will be derived from monitoring the knowledge sharing process . These issues are important in Learning community like a CoPs (both in educational and organisational context), as they promote the processes of knowledge sharing, collaborative learning, and development of collective efficacy among community members. The system kernel o f AI S supports two types of agents (human agent and artificial agents) that help to manage the collaborative learning activity into the community, whereas the integration mechanism supports an agent to interact, coordinate and monitor the activities between agents. AIS for CoPS facilitate the team interaction.This work takes place in the framework of the design of a training environment using collaborative reality like community of practice. In this context, we defend the thesis that it is possible to implement a generic and adaptive intelligent tutoring system (called ITAgAGS) in a collaborative environment, in order to provide pedagogical aid for the learner and pedagogical assistance for the trainer. Our proposal is to integrate ITS in a multi-agent system like JAIS developed during our thesis. Copyright © 2013 SCITEPRESS.

Tokam A.-P.K.,University of Yaounde1 | Tabod C.T.,University of Yaounde1 | Nyblade A.A.,Pennsylvania State University | Julia J.,Pennsylvania State University | And 2 more authors.
Geophysical Journal International | Year: 2010

The Cameroon Volcanic Line (CVL) consists of a linear chain of Tertiary to Recent, generally alkaline, volcanoes that do not exhibit an age progression. Here we study crustal structure beneath the CVL and adjacent regions in Cameroon using 1-D shear wave velocity models obtained from the joint inversion of Rayleigh wave group velocities and P-receiver functions for 32 broad-band seismic stations deployed between 2005 January and 2007 February. We find that (1) crustal thickness (35-39 km) and velocity structure is similar beneath the CVL and the Pan African Oubanguides Belt to the south of the CVL, (2) crust is thicker (43-48 km) under the northern margin of the Congo Craton and is characterized by shear wave velocities ≥4.0 km s-1 in its lower part and (3) crust is thinner (26-31 km) under the Garoua rift and the coastal plain. In addition, a fast velocity layer (Vs of 3.6-3.8 km s-1) in the upper crust is found beneath many of the seismic stations. Crustal structure beneath the CVL and the Oubanguides Belt is very similar to Pan African crustal structure in the Mozambique Belt, and therefore it appears not to have been modified significantly by the magmatic activity associated with the CVL. The crust beneath the coastal plain was probably thinned during the opening of the southern Atlantic Ocean, while the crust beneath the Garoua rift was likely thinned during the formation of the Benue Trough in the early Cretaceous. We suggest that the thickened crust and the thick mafic lower crustal layer beneath the northern margin of the Congo Craton may be relict features from a continent-continent collision along this margin during the formation of Gondwana. © 2010 The Authors Geophysical Journal International © 2010 RAS.

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