6 research outputs found
Biodiversite vegetale et dynamique et reconstitution des jacheres post-culturales dans la foret classee dâIrobo (Sikensi, Cote dâIvoire)
Nous analysons lâimpact de lâagriculture traditionnelle sur la capacitĂ© de reconstitution dans une forĂȘt dense humide sempervirente non soumise Ă des perturbations naturelles majeures. Des relevĂ©s de surfaces complĂ©tĂ©s par des relevĂ©s itinĂ©rants ont permis dâinventorier 448 espĂšces, qui se rĂ©partissent en 301 genres et 92 familles, dont les plus importantes Ă©taient les Fabaceae, les Malvaceae, les Apocynaceae, les Euphorbiaceae, les Moraceae, les Rubiaceae, les Meliaceae et les Annonaceae. Parmi ces espĂšces, 32 (soit 7,14 % de lâeffectif total) sont endĂ©miques Ouest africaines et deux (2) dâentre elles sont endĂ©miques ivoiriennes. La classification hiĂ©rarchique et lâordination des 50 relevĂ©s de vĂ©gĂ©tation a permis dâidentifier cinq (5) groupes sâagençant le long dâun gradient de maturitĂ© forestiĂšre. Les stades pionniers, trĂšs variables, Ă©taient dominĂ©s par une espĂšce invasive : Chromolaena odorata (L.) R. King & H. Robinson. Lâinvasion prĂ©coce des champs par Chromolaena odorata. ne semble pas altĂ©rer durablement la succession secondaire. Les plantations abandonnĂ©es se reconstituent pour atteindre le stade de forĂȘt secondaire, proche de la forĂȘt ancienne La forĂȘt prĂ©sente donc une bonne rĂ©silience.
Mots clĂ©s : BiodiversitĂ© vĂ©gĂ©tale, Successions secondaires, ForĂȘt secondaire, Irobo, CĂŽte dâIvoire
English title:Plant biodiversity and dynamics of regeneration in tropical rain forest (Irobo, Coted dâIvoire)
This study aims at testing whether shifting cultivation contribute to plant diversity in tropical rain forest. For hundred forty species have been recorded in Irobo forest (CĂŽte dâIvoire) during field investigations, distributed among 301 genera and 92 families, the most important being Fabaceae, Malvaceae, Apocynaceae, Euphorbiaceae, Moraceae, Rubiaceae, Meliaceae and Annonaceae. Among those species, 33 (7.14%) are endemic from West Africa, among which only two are endemic from CĂŽte dâIvoire. The hierarchical classification of 50 vegetation releves helped to identify 5 groups along a gradient of maturity. Early-successional stages were dominated by the invasive species Chromolaena odorata (L.) R. King & H. Robinson. The early invasion by Chromolaena odorata did not does not appear to alter secondary succession. Species assembled themselves into plant communities along the successional gradient with respect to their light requirements, suggesting niche partitioning. The succession progressively leads to a secondary forest similar to the primary forest. This forest is highly resilient.
Key-words: Plant biodiversity, Secondary successions, Secondary forest, Irobo, CĂŽte dâIvoir
Co-limitation towards lower latitudes shapes global forest diversity gradients
The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025°âĂâ0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers
Anomalies hematologiques au cours des accidents vasculaires cerebraux a Abidjan des (Cote dâIvoire)
Introduction: En CĂŽte dâIvoire, les accidents vasculaires cĂ©rĂ©braux (AVC) sont deplus en plus frĂ©quents. Les anomalies biochimiques sont dĂ©crites au cours de ces pathologies. Cependant une composante hĂ©matologique est de plus en plus Ă©voquĂ©e. Lâobjectif de cette Ă©tude a Ă©tĂ© de rapporter les anomalies hĂ©matologiques au cours des AVC chez des patients noirs africains Ă Abidjan.MĂ©thodologie: Cette Ă©tude transversale a Ă©tĂ© rĂ©alisĂ©e dans le service de neurologie du CHU de Cocody et le laboratoire de lâInstitut National de SantĂ© publique. LâAVC a Ă©tĂ© objectivĂ© par la TomodensitomĂ©trie. LâhĂ©mogramme, la vitesse de sĂ©dimentation, le bilan de coagulation et les tests spĂ©cialisĂ©s dâhĂ©mostase (D dimĂšres, PAI, RPCa, AAPL) ont Ă©tĂ© effectuĂ©s.RĂ©sultats: LâĂ©tude a concernĂ© 130 patients ĂągĂ©s de 25 Ă 93 ans ,72 cas dâAVCH et 58 cas dâAVC I ont Ă©tĂ© diagnostiquĂ©s, lâHTA Ă©tait le facteur de risque majeur (66,92 %). LâanĂ©mie Ă©tait prĂ©sente chez 57 % des patients, de type hypochrome microcytaire dans les AVC H (62,5 %) et normochrome normocytaire dans les AVC I (53,5 %). Une thrombopĂ©nie notĂ©e dans 17,39 % des cas, la vitesse de sĂ©dimentation accĂ©lĂ©rĂ©e chez la majoritĂ© des patients (83,48 %). Le bilan de coagulation de routine Ă©tait en gĂ©nĂ©ral normal indĂ©pendamment du type dâAVC (77,91 %). Des taux Ă©levĂ©s de DDimĂšres (88,76 %) et de PAI (35ng/ml), la positivitĂ© aux AAPL (27 %) et une absence de la RPCa ont Ă©tĂ© observĂ©s.Conclusion: Des anomalies hĂ©matologiques ont Ă©tĂ© observĂ©es au cours des AVC chez le noir africain. La prise en compte de celles-ci permettrait un meilleur suivi des patients atteints dâAVC.Mots clĂ©s: AVC, anĂ©mie, thrombophilie, D dimĂšres, AbidjanEnglish Title: Haematological abnormalities in the stroke in Abidjan (Ivory Coast)English AbstractIntroduction: In Ivory Coast, stroke is becoming more and more. Biochemicalabnormalities are common in these pathologies. However hematologic component is increasingly raised. The objective of the study was to report the hematological abnormalities in the stroke among black African patients in Abidjan.Methodology: This cross-sectional study was conducted in the neurology department of the University Hospital of Cocody and the laboratory of the National Institute of  Public Health. The stroke was objectified by CT Scanning. The complete blood count, erythrocyte sedimentation, coagulation balance sheet and specialized tests of hemostasis (D dimer, PAI, APCR, AAPL) were performed.Results: One hundred and thirty patients aged between 25 and 93 years had been enrolled, 72 cases of hemorrhagic stroke and 58 cases of ischemic stroke have been diagnosed, High blood pressure was the major risk factor (66.92%). Anemia was present in 57% of patients, of type hypochromic microcytic in hemorrhagic stroke (62.5%) and normochromic normocytic in ischemic stroke (53.5%). Thrombocytopenia noted in 17.39% of cases, accelerated sedimentation rate in the majority of patients (83.48%). Routine coagulation profile was normal in general regardless of the type of stroke (77.91%). High levels of both D-dimer (88.76%) and IPA (35 ng / ml), positive to AAPL (27%) and absence of APC resistance have been observed.Conclusion: Hematological abnormalities were observed in stroke among the black African. Consideration of these would ensure better monitoring of stroke patients.Keywords: Stroke, anemia, thrombophilia, D-dimer, Abidja
Evaluation de lâactivite antifalcimiante de differents extraits des graines de Cajanus cajan (Fabacees) sur les drepanocytes a Abidjan-Cote dâIvoire
Les coĂ»ts onĂ©reux du traitement dans la drĂ©panocytose conduisent, les patients Ă sâorienter vers la mĂ©decine traditionnelle. Une Ă©tude antĂ©rieure a montrĂ© lâactivitĂ© antifalcimiante de lâextrait aqueux des graines de Cajanus cajan (FabacĂ©es). En vue dâidentifier lâextrait le plus actif, il a Ă©tĂ© proposĂ© comme objectif dâĂ©valuer in vitro lâeffet antifalcimiant de diffĂ©rents extraits des graines de Cajanus cajan. LâĂ©tude de lâactivitĂ© antifalcimiante sâest faite sur les prĂ©lĂšvements sanguins de 32 drĂ©panocytaires homozygotes SSFA2. AprĂšs induction de la falciformation des globules rouges, lâajout dâun extrait dans chaque tube a permis dâĂ©valuer lâactivitĂ© antifalcimiante par le dĂ©compte des drĂ©panocytes au microscope optique. Les extraits des graines de Cajanus cajan contiennent des stĂ©rols, polyterpĂšnes, polyphĂ©nols, des flavonoĂŻdes et des alcaloĂŻdes. Tous les extraits diminuaient le taux de drĂ©panocytes dâenviron 60% aprĂšs 30 mn de contact. Cette Ă©tude a permis de montrer que les diffĂ©rents extraits des graines de Cajanus cajan possĂšdent des vertus antifalcimiantes tout comme lâextrait aqueux.Mots clĂ©s: Cajanus cajan, extraits, activitĂ© antifalcimiante, AbidjanEnglish Title: Evaluation of the antisickling activity of different extracts of Cajanus cajan (Fabacees) seeds on sickle cells in Abidjan-Cote dâIvoireEnglish AbstractThe expensive costs of treatment in sickle cell disease lead patients to move towards traditional medicine. A previous study showed the antifalcimiant activity of the aqueous extract of the seeds of Cajanus cajan (Fabaceae). In order to identify the most active extract, it has been proposed to evaluate in vitro the antifalcimiant effect of different extracts of Cajanus cajan seeds. The study of antifalcimiante activity was done on the blood samples of 32 SSFA2 homozygous sickle cell patients. After induction of sickling of the red blood cells, the addition of an extract in each tube made it possible to evaluate the antifalcimiant activity by the counting of the sickle cells under an optical microscope. The extracts of Cajanus cajan seeds contain sterols, polyterpenes, polyphenols, flavonoids and alkaloids. All extracts decreased the sickle cell count by about 60% after 30 minutes of contact. This study has shown that the different extracts of the seeds of Cajanus cajan possess antifalcimiante virtues just like the aqueous extract.Keywords: Cajanus cajan, extracts, antifalcimiant activity, Abidja
Multidimensional tropical forest recovery
Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation
Multidimensional tropical forest recovery
Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation