Assessing the Usefulness of \u3cem\u3eSenna obtusifolia\u3c/em\u3e, an Invasive Plant Species in West Africa Rangelands

Senna obtusifolia is a less appreciated plant species. Its invasion has led to the disappearance of several herbaceous species of interest in West Africa rangelands. As adaptation strategy, people use it to substitute for those that have disappeared. This study aimed to assess the importance of this species for animal and local ethnic groups according to two contrast climate zones in Burkina Faso. Ethnobotanic survey mixed with direct observations on the field were conducted. Three hundred (300) people from height (8) ethnic groups were interviewed. The survey technique was semi-structured interviews using a previously tested semi-structured questionnaire. At the early stage of the rainy season, Senna obtusifolia is one of the plants available in abundance. Animals graze on the leaves of the seedlings. During the dry season, animals graze on the dry pods of Senna obtusifolia due to lack of fodder. Grazing dry pods also reduces the high rate of tree pruning. In addition, local population uses Senna obtusifolia in eight (8) categories. The most important are food (100%) and construction (46%). Sahelian people use the species more than Sudanian people. This study revealed the benefit of Senna obtusifolia to animals and people. The use of this species could be seen as an adaptive strategy to the negative ecological invasion of the species. Furthermore, these results could guide the formulation of management policies and how to further value invasive species

Exploring Drivers of Invasiveness of the Plant Species \u3ci\u3eSenna obtusifolia\u3c/i\u3e in Rangelands to Secure Forage Production in West Africa

Rangelands in Sahelian countries are continuously over-grazed decreasing forage resources and causing rapid environmental changes. Senna obtusifolia is a less palatable plant species that becomes increasingly invasive. This research explored drivers of its invasiveness in the perspective to propose solutions to secure forage production in the pastoral reserves. Species composition and herbaceous aboveground biomass were assessed in rangelands with different levels of invasion of Senna obtusifolia along a climatic and land-use pressure gradient. A greenhouse experiment was conducted to test the competitiveness of this species. The development of Senna obtusifolia in rangelands affected significantly forage quantity. Indeed the biomass of the others herbaceous species decreased but not the species richness. The overgrazing of Sahelian rangelands combined to the floristic selection operated by livestock reduced the abundance of fodder species and fostered the expansion of S. obtusifolia. Moreover, S. obtusifolia had a good germination rate with a rapid growth that made it more competitive. Thus, in the interspecific competition experiment, the aboveground biomass of S. obtusifolia was not influenced when associated to legume, grass and perennial grass species respectively. After 3 years of full protection experiment, the abundance of S. obtusifolia decreased, hence its invasiveness in rangelands should be supported by the mixed effect of disturbance factors as grazing and drought that lead several plant species to be vulnerable and favor undesirable species expansion. The control of S. obtusifolia expansion is conditionned by the reformulation of the land management systems and the promotion of sustainable environmental policies

Equations for the estimation of strong ground motions from shallow crustal earthquakes using data from Europe and the Middle East : vertical peak ground acceleration and spectral acceleration

This article presents equations for the estimation of vertical strong ground motions caused by shallow crustal earthquakes with magnitudes M w 5 and distance to the surface projection of the fault less than 100km. These equations were derived by weighted regression analysis, used to remove observed magnitude-dependent variance, on a set of 595 strong-motion records recorded in Europe and the Middle East. Coefficients are included to model the effect of local site effects and faulting mechanism on the observed ground motions. The equations include coefficients to model the observed magnitude-dependent decay rate. The main findings of this study are that: short-period ground motions from small and moderate magnitude earthquakes decay faster than the commonly assumed 1/r, the average effect of differing faulting mechanisms is similar to that observed for horizontal motions and is not large and corresponds to factors between 0.7 (normal and odd) and 1.4 (thrust) with respect to strike-slip motions and that the average long-period amplification caused by soft soil deposits is about 2.1 over those on rock sites

La tuberculose iléo-caecale : à propos de deux cas au CHU Yalgado Ouedraogo

La tuberculose iléo-caecale est rare et simule souvent un abdomen chirurgical aigü. L'objectif de ce travail a été de préciser les difficultés diagnostiques et thérapeutiques de cette affection dans le milieu burkinabè. Il a été recensé deux cas de tuberculose iléo-caecale en cinq ans, dans le service de chirurgie viscérale du CHU-YO. Il s’est agi d’une femme et d’un homme. L’âge moyen était de 61,5 ans avec des extrêmes de 61 et 62 ans. Dans un cas, il a été noté des antécédents de tuberculose. La sérologie VIH était négative dans les 2 cas. Ces deux malades ont été reçus en urgence pour un syndrome abdominal aigu. Le diagnostic de tuberculose iléo-caécale a été soupçonné en per-opératoire devant une masse inflammatoire de la jonction iléocaecale avec de nombreuses adénopathies mésentériques. L’examen anatomopathologique de la pièce opératoire d’hémicolectomie droite, a mis en évidence des lésions caséeuses folliculaires épithéliales et gigantocellulaires. Ces lésions ont orienté vers le diagnostic de tuberculose iléocoécale. Le traitement antituberculeux instauré était conforme au protocole du programme national burkinabè de lutte contre la tuberculose. L’évolution a été favorable dans les deux cas.Mots clés: tuberculose - jonction iléocaécale - traitement antituberculeux - chirurgieEnglish AbstractThe ileo-caecal tuberculosis is rare and often simulates a surgical acute abdomen. The objective of this work was to clarify the diagnostic and therapeutic difficulties of this disease in the Burkina community. It was identified two cases of ileo-caecal tuberculosis in five years in the visceral surgery department of CHU-YO. It came from 01 woman and 01 man. The average age was 61.5 years with extremes of 61 and 62 years. In one case, it was noted a history of tuberculosis. The HIV serology was negative in the two cases. These two patients were received in emergency for acute abdominal syndrome. The diagnosis of ileocoecal tuberculosis was suspected intraoperatively to an inflammatory mass of ileo-caecal junction with many mesenteric lymphadenopathy. Pathological examination of the surgical specimen of the right hemicolectomy, showed caseous, follicular, epithelial and gigantocellular lesions. These lesions were oriented ileocaecal tuberculosis diagnostic. The introduction of the treatment antituberculosis was consistent with the national protocol program against tuberculosis of Burkina Faso. The outcome was favorable in two cases.Keywords: tuberculosis - ileocecal jonction - antituberculeux treatment - surger