Etude écologique du Parc National de Mozogo-Gokoro (Cameroun): prospections préliminaires de la flore ligneuse et du sol pour sa conservation et son aménagement

La conservation et la gestion rationnelle des aires protégées requièrent des études préalables de caractérisations écologique et floristique. Dans cette optique, il a été envisagé des prospections de base de la flore ligneuse et du sol pour l’aménagement du Parc National de Mozogo-Gokoro (PNMG), situé en zone sahélo-soudanienne, région de l’Extrême-Nord au Cameroun. Les données obtenues décrivent un sol favorable à la production végétale : texture sablo-limoneuse, activités biologiques présentes et absence d’érosion. La végétation présente une physionomie de forêt sèche claire à dense. La diversité compositionnelle montre sa grande richesse floristique, avec 62 espèces de ligneux identifiées. L’indice de Shannon est évalué à 3,75 bits avec une équitabilité de 0,84. Dans sa structure, il peut être relevé une densité très élevée (2972 tiges/hectare) et la forte représentativité des moyennes et hautes tiges, preuves de sa grande préservation. Les types phytogéographiques rapprochent la végétation des zones soudaniennes à guinéennes. Ces caractéristiques peuvent lui conférer le statut d’écosystème de référence montrant un transfert d’espèces des zones guinéennes et soudaniennes au sahélien, malgré les menaces anthropiques notées. Ces spécificités floristiques peuvent s’expliquer par les mesures de conservation appliquées, la pédologie et la topographie (bas-fond, piémont). L’obtention d’attributs vitaux, de façon plus approfondie, pourrait confirmer ces analyses et contribuer plus significativement à son processus d’aménagement.Mots clés : Pré-inventaire, diversité compositionnelle, structure, écosystème de référence, menaces anthropiques, aire protégé

Essai d’analyses de la conception paysanne de l’évolution, de la gestion et de l’utilité du Parc National de Mozogo-Gokoro (Cameroun) en vue de son aménagement

Cet essai d’exploration du milieu humain riverain du Parc National de Mozogo-Gokoro est une démarche visant sa conservation et son aménagement, en exploitant des indicateurs facilement compréhensibles. Une enquête socio-économique à orientations écologiques a été réalisée afin d’apprécier la perception paysanne de l’évolution spatio-temporelle, compositionnelle et structurale du parc, de son utilité, et de sa gestion avec confrontation des résultats à la vision de l’administration forestière locale. Les résultats ont montré que c’est un écosystème qui a subi une forte pression anthropique, et l’effet de la sècheresse avec une trajectoire régressive. Plusieurs espèces animales et végétales sont signalées en disparition ou en diminution dans le Parc, reflétant un recul de la biodiversité. Son utilité est illustrée par la diversité des ressources (Produits Forestiers Non Ligneux, bois de service et d’énergie) prélevées ou dont le besoin a été exprimé par la population riveraine, indiquant par ailleurs une gestion non conforme à la réglementation. Des orientations d’aménagement, découlant de cette perception, ont été proposées afin d’atténuer la dynamique régressive amorcée et causée par l’absence d’un plan de gestion participative, renforçant sa protection intégrale.Mots clés : Enquête, dynamique spatio-temporelle, perception, population, végétation, protectio

Geographic Distribution of Childbirth among Adolescents in Cameroon from 2003 to 2005

Objective. To determine the frequency and the trend of adolescents (10–19 years) in childbirth within a period of 3 years in referral maternity units in Cameroon. Method. Descriptive and retrospective study for a 3-year period (2003–2005) in referral maternity units headed by a qualified Obstetrician-Gynecologist. We analyzed the trend and geographic distribution of 8222 adolescent deliveries over 3 years. Epi Info 3.5 software was used for data analysis. Chi square test for trend was used to assess the contribution of adolescent deliveries over years. The trend was considered significant if P < .05. Results. During the period of the study, there was a total of 8387 deliveries. We excluded 165 women because of lack of information about age. We therefore included a total of 8222 adolescent deliveries. Overall, the contribution of adolescents to deliveries ranged from 6.87% to 26.51%, depending on the region with a national mean of 14.23%. Adolescents aged 16 or less contributed to 2.82% of deliveries while those aged from 17 to 19 contributed to 11.41%. The contribution of adolescents to deliveries decreased significantly over 3 years (P < .0001). Conclusion. The study underscores the importance of Public Health programs in strengthening maternity services for adolescents in Cameroon while taking into consideration geographic differences

Evaluation of Performances of Calcined Laterite and Oyster Shell Powder Based Blended Geopolymer Binders

This work consisted in characterizing of calcined laterite and oyster shell powder based blended geopolymer binders. To do this, raw laterite taken from Soa in the city of Yaoundé and oyster shells extracted from Mouanko in the Sanaga-Maritime were initially air-dried, then dried at 105 °C, before being calcined at 500 °C and 200 °C respectively for 2 hours. These samples were subjected to preliminary studies, i.e. determination of their chemical and mineralogical compositions, particle size distributions, densities, as well as thermal analysis for the synthesis of geopolymer binders. X-ray diffractometry, thermal and gravimetric analysis were carried out on the oyster shell powder and laterite, in order to elucidate the time and degree of calcination of the two samples, the evolution of the linear shrinkage, the setting time as well as the compressive and flexural strengths of the geopolymer binders. The results obtained show that oyster shells are rich in CaCO3 and contain crystalline phases, while laterite is rich in silica, iron (FeCO3) and alumina (Al2O3). The geopolymer samples: Lat + 0% oyster shells have a setting time between 125 and 168 min for a compressive strength of about 47 MPa. The peak strength is observed around 15% addition of oyster shell powder, i.e. 53.5 MPa at 28 days with an increased setting time. This strength was decreased from 25 % of addition of oyster shells, despite the increase observed in the setting time. It appears from this study that the addition of 15% oyster shell increases the compressive strength of the geopolymer, but also leads to a considerable decrease in absorption rate. Above this rate, the compressive strength decreases drastically and concomitantly the setting time increases

Contribution de l’échographie dans le dépistage et le diagnostic des cancers du sein : une expérience de Yaoundé, Cameroun

L&#8217;objectif de cette &#233;tude &#233;tait de rechercher la contribution de l&#8217;&#233;chographie dans le d&#233;pistage et le diagnostic des l&#233;sions mammaires &#224; Yaound&#233;, Cameroun. Il s&#8217;agissait de d&#233;crire les anomalies cliniques, &#233;chographiques, &#233;ventuellement anatomopathologiques pour des l&#233;sions suspectes et les confronter. L&#8217;&#233;tude &#233;tait transversale descriptive sur une p&#233;riode de 12 mois ; constitu&#233;e de 103 femmes &#226;g&#233;es de 45 ans et plus. La moyenne d&#8217;&#226;ge a &#233;t&#233; de 53 ans. La douleur mammaire &#233;tait le principal sympt&#244;me (21,4%). Les anomalies &#233;chographiques ont &#233;t&#233; retrouv&#233;es chez 43 femmes (41,7%). Les plus fr&#233;quentes ont &#233;t&#233; les nodules tissulaires (29,1%). Les l&#233;sions d&#8217;allure b&#233;nigne (ACR2) ont &#233;t&#233; retrouv&#233;es chez 26 (25,24%) femmes et celles suspectes de malignit&#233; (ACR3, ACR4, et ACR5) chez 17 (16,5%) dont 14 ont b&#233;n&#233;fici&#233; d&#8217;une biopsie. L&#8217;examen anatomopathologique a r&#233;v&#233;l&#233; 8 cas de carcinomes (57,14%). L&#8217;&#233;chographie bien conduite dans un contexte socio-&#233;conomique d&#233;favoris&#233; oriente le diagnostic de cancer du sein

Glycosylation characterization of therapeutic mAbs by top- and middle-down mass spectrometry

A reference monoclonal antibody IgG1 and a fusion IgG protein were analyzed by top- and middle-down mass spectrometry with multiple fragmentation techniques including electron transfer dissociation (ETD) and matrix-assisted laser desorption ionization in-source decay (MALDI-ISD) to investigate heterogeneity of glycosylated protein species. Specifically, glycan structure, sites, relative abundance levels, and termini structural conformation were investigated by use of Fourier transform ion cyclotron resonance (FT-ICR) or high performance liquid chromatography electrospray ionization (HPLC-ESI) linked to an Orbitrap. Incorporating a limited enzymatic digestion by immunoglobulin G-degrading enzyme Streptococcus pyogenes (IdeS) with MALDI-ISD analysis extended sequence coverage of the internal region of the proteins without pre-fractionation. The data in this article is associated with the research article published in Journal of Proteomics (Tran et al., 2015)

MassCode Liquid Arrays as a Tool for Multiplexed High-Throughput Genetic Profiling

Multiplexed detection assays that analyze a modest number of nucleic acid targets over large sample sets are emerging as the preferred testing approach in such applications as routine pathogen typing, outbreak monitoring, and diagnostics. However, very few DNA testing platforms have proven to offer a solution for mid-plexed analysis that is high-throughput, sensitive, and with a low cost per test. In this work, an enhanced genotyping method based on MassCode technology was devised and integrated as part of a high-throughput mid-plexing analytical system that facilitates robust qualitative differential detection of DNA targets. Samples are first analyzed using MassCode PCR (MC-PCR) performed with an array of primer sets encoded with unique mass tags. Lambda exonuclease and an array of MassCode probes are then contacted with MC-PCR products for further interrogation and target sequences are specifically identified. Primer and probe hybridizations occur in homogeneous solution, a clear advantage over micro- or nanoparticle suspension arrays. The two cognate tags coupled to resultant MassCode hybrids are detected in an automated process using a benchtop single quadrupole mass spectrometer. The prospective value of using MassCode probe arrays for multiplexed bioanalysis was demonstrated after developing a 14plex proof of concept assay designed to subtype a select panel of Salmonella enterica serogroups and serovars. This MassCode system is very flexible and test panels can be customized to include more, less, or different markers

Salmonella Strains Isolated from Galápagos Iguanas Show Spatial Structuring of Serovar and Genomic Diversity

It is thought that dispersal limitation primarily structures host-associated bacterial populations because host distributions inherently limit transmission opportunities. However, enteric bacteria may disperse great distances during food-borne outbreaks. It is unclear if such rapid long-distance dispersal events happen regularly in natural systems or if these events represent an anthropogenic exception. We characterized Salmonella enterica isolates from the feces of free-living Galápagos land and marine iguanas from five sites on four islands using serotyping and genomic fingerprinting. Each site hosted unique and nearly exclusive serovar assemblages. Genomic fingerprint analysis offered a more complex model of S. enterica biogeography, with evidence of both unique strain pools and of spatial population structuring along a geographic gradient. These findings suggest that even relatively generalist enteric bacteria may be strongly dispersal limited in a natural system with strong barriers, such as oceanic divides. Yet, these differing results seen on two typing methods also suggests that genomic variation is less dispersal limited, allowing for different ecological processes to shape biogeographical patterns of the core and flexible portions of this bacterial species' genome

A highly sustainable route to pyrrolidonederivatives - direct access to new biosourced solvents

International audienceAccess to a series of 5-methylpyrrolidone derivatives is described directly using the biosourced levulinic acid in the absence of any additive, catalyst or solvent. The highly selective reaction proceeds with an E-factor as low as 0.2. Products are recovered in very good yields after a simple distillation

Rupture uterine au centre hospitalier et universitaire de Yaounde au Cours des 10 derniere annees (1997-2006)

No abstractClinics in Mother and Child Health Vol. 4 (1) 2007: pp. 651-65