The influence of DACCIWA radiosonde data on the quality of ECMWF analyses and forecasts over southern West Africa

During the DACCIWA (Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa) field campaign ∼900 radiosondes were launched from 12 stations in southern West Africa from 15 June to 31 July 2016. Subsequently, data-denial experiments were conducted using the Integrated Forecasting System of the European Centre for Medium-range Weather Forecasts (ECMWF) to assess the radiosondes\u27 impact on the quality of analyses and forecasts. As observational reference, satellite-based estimates of rainfall and outgoing long-wave radiation (OLR) as well as the radiosonde measurements themselves are used. With regard to the analyses, the additional observations show positive impacts onwinds throughout the troposphere and lower stratosphere, while large lower-tropospheric cold and dry biases are hardly reduced. Nonetheless, downstream, that is farther inland from the radiosonde stations,we find a significant increase (decrease) in low-level night-time temperatures (monsoon winds) when incorporating the DACCIWA observations, suggesting a possible linkage via weaker cold air advection fromthe Gulf of Guinea. The associated lower relative humidity leads to reduced cloud cover in the DACCIWA analysis. Closer to the coast and over Benin and Togo, DACCIWA observations increase low-level specific humidity and precipitable water, possibly due to changes in advection and vertical mixing. During daytime, differences between the two analyses are generally smaller at low levels. With regard to the forecasts, the impact of the additional observations is lost after a day or less. Moderate improvements occur in low-level wind and temperature but also in rainfall over the downstream Sahel, while impacts on OLR are ambiguous. The changes in precipitation appear to also affect high-level cloud cover and the tropical easterly jet. The overall rather small observation impact suggests that model and data assimilation deficits are the main limiting factors for better forecasts inWest Africa. The new observations and physical understanding from DACCIWA can hopefully contribute to reducing these issues

Induction et prolifération de cals à partir de l’axe embryonnaire du Voandzou [Vigna subterranea (L.) Verdc. Fabaceae] : effet de la segmentation de l’explant, des phytohormones, de la source de carbone et du génotype

Le Voandzou [Vigna subterranea, (L.) Verdc.], occupe une place importante dans les stratégies élaborées pour assurer la sécurité alimentaire en Afrique subsaharienne. Le développement de systèmes de régénération in vitro de plantes, préalable au transfert de gènes nécessite l’établissement de conditions optimales de la callogenèse. Au cours du présent travail, l’étude des facteurs influençant l’induction et la prolifération des cals chez le Voandzou a été réalisée. L’axe embryonnaire issu de graines matures a été placé sur le milieu de base de Murashige et Skoog (1962) additionné avec les vitamines B5 et supplémenté avec différentes concentrations et combinaisons de phytohormones. Après quatre semaines de culture, les résultats ont montré que l’induction et la prolifération de cals ont été favorisées avec le 2,4-D (0,5 mg/l). La partie basale de l’axe embryonnaire a été la zone la plus favorable à la callogenèse. La meilleure source de carbone a été le saccharose à la concentration optimale de 84 mM. Les meilleurs taux d’induction (100 %) et de prolifération de cals (3) ont été exprimés avec les écotypes Ci2, Ci3, Ci4, Ci5, Ci6, Ci7, Ci10 et Ci21.Mots-clés : voandzou, axe embryonnaire, callogenèse, phytohormones.Callus induction and proliferation from embryonic axis in Bambara groundnut [Vigna subterranea (L.) Verdc. Fabaceae]: effect of explants section, plant growth regulators, carbon source and genotypeBambara groundnut [Vigna subterranea (L.) Verdc. ] contributes to food security in sub-Saharan Africa. Development of efficient systems of in vitro plant regeneration a prerequisite to gene transfer requires establishment of optimal conditions for callus formation. In this work, factors influencing callus induction and proliferation in Bambara have been studied. Embryonic axis derived mature seeds were placed on Murashige and Skoog (1962) medium supplemented with vitamins B5 (MSB5), including different concentrations and combinations of plant growth regulators. After four weeks of culture, results showed that 2,4-D (0.5 mg/L) exhibited the best frequency and proliferation index of callus. Basal part of embryonic axis was the explants of choice for callus induction and proliferation. Sucrose at optimum concentration of 84 mM was favorable to the process of callus formation. Highest callus induction frequency (100 %) and proliferation index (3) were expressed by ecotypes Ci2, Ci3, Ci4, Ci5, Ci6, Ci7, Ci10 and Ci21.Keywords : bambara groundnut, embryonic axis, callogenesis, plant growth regulators

Étude de la durabilité économique et environnementale de la production de manioc sur ferralsols

Objective: To evaluate the components of the sustainability of cassava cropping systems that rely on alley cropping. Methodology and results: The study consisted to cultivate improved cassava ( Yavo ) / green soybeans ( Mung Bean) / Gliricidia sepium with a basal dressing ( NPK [ 20: 36 : 36] or chicken manure [10 t / ha] ) compared to the traditional system consisting of a local variety of cassava and peanut intercropping on ferralsols. The sum of the new factors of production allowed a significant increase in the food output. In addition to bean production, organic manure and, potentially, fuel wood from G. sepium, the yield of cassava of the introduced variety Yavo was 40 t/ha compared to 13 t/ha in the traditional. The plant architecture of the new systems allowed a good soil cover, thus reducing the frequency of weeding, done traditionally by women. Conversely, workload for men increased. The new system was also economically viable. Conclusion and application of findings: As a whole, the suggested system appears to have a potential to contribute to agronomic, environmental, economic and social sustainability. The new systems could be recommended for the intensification of the cassava crop.Keywords: cassava, Gliricidia sepium, green soya, ferralsol, sustainability

Dynamique du peuplement des Oiseaux d’une riziculture et ses environs dans la zone humide d’importance internationale de Grand-Bassam

Objectifs : cette étude vise à actualiser les connaissances sur l’avifaune de la zone humide de Grand- Bassam et à déterminer les variations annuelles du peuplement d’Oiseaux. Méthodologie et résultats : l’avifaune a été inventoriée de janvier 2011 à février 2013 par la méthode des transects itinérants avec des points d’arrêt de 15 minutes aux endroits appropriés. Au total, 218 espèces appartenant à 51 familles et 17 ordres ont été identifiées. La présente étude révèle 49 espèces nouvellement observées dans la zone humide de Grand-Bassam. Le peuplement d’Oiseaux rencontré renferme un grand nombre d’individus dont le pic annuel est atteint en juillet. Ce peuplement est dominé par les populations de tisserin gendarme (Ploceus cucullatus), de travailleur à tête rouge (Quelea erythrops) et de capucin nonnette (Spermestes cucullata). Conclusion et application : cette étude contribue à une meilleure connaissance de l’avifaune de la zone humide de Grand-Bassam et fournit des données préliminaires sur l’importance numérique des différentes espèces inventoriées. Face à une anthropisation de plus en plus prononcée de la zone humide, liée au développement de la ville et aux activités agricoles, ces résultats serviront de base scientifique à l’établissement d’un système de gestion durable de l’avifaune dans les rizicultures.Mots clés : Oiseaux, Biodiversité, Dynamique du peuplement, Zone humide Riziculture, Grand- Bassam.Dynamics of birds’ community, of international importance in the rice fields and surrounding areas in the Grand-Bassam wetland.  Objectives: This study aims to update the knowledge on birds’ community of the Grand-Bassam wetland and it annual variation. Methodology and Results: Birds were surveyed from January 2011 to February 2013 by the method of line transects with a 15 minutes points count in the appropriated places. A total 218 species belonging to 51 families of 17 orders were identified. The study found 49 newly observed species in the Grand- Bassam Ramsar site. The birds’ community is rich of an important number of individuals which maximum is in July. This bird’s community is dominated by populations of Village Weaver( Ploceus cucullatus),, Red-headed Quelea (Quelea erythrops) and Bronze Mannikin (Spermestes cucullata).. Conclusion and application: This study has contributed to a better knowledge of the avifauna of Grand- Bassam Ramsar site and provides preliminary data on the size of the different species. Facing a more pronounced anthropisation due to the development of the city and farming, these results can served as a first scientific basis for the establishment of a sustainable management of the avifauna in ricefields.Keywords: Birds, Biodiversity, Community Dynamics, Wetlands, Ricefield, Grand-Bassa

Influence de la teneur en ciment sur les propriétés thermomécaniques des blocs d’argile comprimée et stabilisée

Ce travail vise à déterminer la résistance à la compression et la conductivité thermique des blocs à base d’argile comprimée et stabilisée au ciment d’une part et à étudier la variation de ces propriétés en fonction de la teneur en ciment d’autre part. Les mesures réalisées indiquent que la résistance des blocs sans ciment est de 3,7 MPa par « voie sèche » pour une conductivité thermique de 0,91 Wm-1K-1 (déterminée à l’aide d’un fluxmètre). L’incorporation de ciment entraine une variation de ces deux propriétés. Ainsi on note d’abord une baisse de la résistance suivie d’une augmentation au delà de 4% de ciment. Toutefois la conductivité thermique des blocs ayant les teneurs en ciment les plus importantes reste proche de celle des blocs sans ciment.Mots-clés: bloc d’argile, ciment portland, stabilisation, résistance en compression, conductivité thermique. Influence of cement content on the thermomechanical properties of compressed and stabilized clay blocks This work aims to determine the compressive strength and the thermal conductivity of clay compressed blocks and stabilized with cement and to study the influence of the cement ratio on these characteristics of the blocks. The resistance of blocks without cement is (determined at dry state) is 3.7 MPa and measurements made with a fluxmeter show that the thermal conductivity of these blocks is 0,91 Wm-1 K-1. The results show also that the thermal conductivity and the compressive strength of the blocks vary according to the cement ratio. However the thermal conductivity of the blocks with high cement ratio is close to that of the blocks without cement.Keywords: clay blocks, Portland cement, stabilization, compressive strength, thermal conductivity

Climate Variability in the Sudano-Guinean Transition Area and Its Impact on Vegetation: The Case of the Lamto Region in Côte D’Ivoire

Based on unique 50-year datasets from 1962 to 2011, this study diagnoses the variability of climate at Lamto (6.13°N, 5.02°W) in Côte d’Ivoire. A combined pluviothermal index is used to identify climate regions of West Africa. The interdecadal change of the climate is analyzed along with a discussion on the West African Monsoon (WAM) circulation. The impact of vegetation is also analyzed. It is shown that Lamto has mainly a subhumid climate but, in some particular years, this area has a humid climate. Two decades (1962–1971 and 2002–2011) exhibit rainfall excess and the last three ones (1972–1981, 1982–1991, and 1992–2001) show a rainfall deficit that affected West Africa in the early 1970s. The meridional wind field from 1000 hPa to 700 hPa is used to study the WAM variability. The level of the WAM is the lowest (~860–890 hPa) during the active period of the northern wind coming from the Sahara desert (November–February). During 1962–1971 and 2007–2009, the depth of the monsoon at Lamto reaches 300 hPa with an increase in the rainfall. A relationship between potential evapotranspiration and the climate highlights rainfall deficit in 1969 and rainfall excess in 2001–2011

Efficacy of triclabendazole and albendazole against Fasciola spp. infection in cattle in Côte d'Ivoire: a randomised blinded trial

Triclabendazole is the anthelminthic of choice for the treatment of fascioliasis, however, it is not yet registered in many countries. Therefore, we investigated the efficacy of a single-dose of triclabendazole (12 mg/kg) or albendazole (15 mg/kg) against Fasciola spp. infection in cattle on farms in the northern part of Cote d'Ivoire in a randomized clinical trial. Faecal samples were obtained from 196 cattle, of which 155 (79.1%) were found positive for Fasciola spp. by the sedimentation technique. Cattle infected with Fasciola spp. were randomly allocated (3:3:1) to receive triclabendazole (n=66), albendazole (n=67) or left untreated to serve as control (n=22). Follow-up faecal samples were collected on days 21, 28, 90 and 188 post-treatment. No adverse events were observed as reported by the farmer in any of the treatment groups. The proportion of non-egg shedding cattle (PNES), assessed at day 21 (primary outcome), was significantly higher in cattle treated with triclabendazole (95.4%) compared to those receiving albendazole (70.3%; odds ratio [OR] 0.11, 95% confidence interval [CI] 0.03-0.39, p <0.001). The egg reduction rate (ERR) expressed as number of eggs per gram of faeces (epg), a secondary endpoint assessed at day 21 post-treatment, was significantly higher in the triclabendazole arm (arithmetic mean (AM) ERR=99.8%) than in the albendazole arm (AM ERR=92.2%), with a difference of 7.6%-points (95% CI: 0.9-14.5%-points, p=0.03). Reinfection rates at days 90 and 188 post-treatment (secondary endpoint) were lower in the triclabendazole arm (5.3% and 18.5%) compared to the albendazole arm (23.5% and 33.3%). This is the first report of efficacy of triclabendazole against Fasciola spp. in naturally infected cattle in Cote d'Ivoire. Our results confirm that triclabendazole is the most effective treatment of fascioliasis and therefore, should be considered for the control of livestock fascioliasis; if resources allow in combination with intermediate host snail control and raising farmers awareness of pasture and livestock management to avoid reinfection

Detection and identification of pathogenic trypanosome species in tsetse flies along the Comoe River in Cote d'Ivoire

In order to identify pathogenic trypanosomes responsible for African trypanosomiasis, and to better understand tsetse-trypanosome relationships, surveys were undertaken in three sites located in different eco-climatic areas in Cote d'Ivoire during the dry and rainy seasons. Tsetse flies were caught during five consecutive days using biconical traps, dissected and microscopically examined looking for trypanosome infection. Samples from infected flies were tested by PCR using specific primers for Trypanosoma brucei s.l., T. congolense savannah type, T. congolense forest type and T. vivax. Of 1941 tsetse flies caught including four species, i.e. Glossina palpalis palpalis, G. p. gambiensis, G. tachinoides and G. medicorum, 513 (26%) were dissected and 60 (12%) were found positive by microscopy. Up to 41% of the infections were due to T. congolense savannah type, 30% to T. vivax, 20% to T. congolense forest type and 9% due to T. brucei s.l. All four trypanosome species and subgroups were identified from G. tachinoides and G. p. palpalis, while only two were isolated from G. p. gambiensis (T. brucei s.l., T. congolense savannah type) and G. medicorum (T. congolense forest, savannah types). Mixed infections were found in 25% of cases and all involved T. congolense savannah type with another trypanosome species. The simultaneous occurrence of T. brucei s.l., and tsetse from the palpalis group may suggest that human trypanosomiasis can still be a constraint in these localities, while high rates of T. congolense and T. vivax in the area suggest a potential risk of animal trypanosomiasis in livestock along the Comoe River

Prevalence and distribution of livestock schistosomiasis and fascioliasis in Côte d'Ivoire: results from a cross-sectional survey

BACKGROUND: Schistosoma and Fasciola are zoonotic parasites of public health and veterinary importance. However, while the epidemiology of schistosomiasis in humans is well studied, little is known about fascioliasis and schistosomiasis in livestock in Cote d'Ivoire. This study aimed to determine the prevalence and the distribution of livestock schistosomiasis and fascioliasis across Cote d'Ivoire. In 2018, we conducted a cross-sectional survey in abattoirs and farms in 13 departments of Cote d'Ivoire. In abattoirs, the mesenteric veins and livers of slaughtered cattle, sheep and goats were examined for adult Schistosoma and Fasciola flukes. Faeces from live cattle, goats and sheep were collected and examined for Schistosoma and Fasciola eggs using a sedimentation technique. RESULTS: A total of 386 cattle, 174 goats and 151 sheep from abattoirs and 435 cattle, 22 goats and 176 sheep from farms were sampled. The observed prevalence of schistosomiasis was higher in slaughtered animals. Fascioliasis was more prevalent in farm animals. The prevalence of schistosomiasis in slaughtered cattle varied between 5.9% (95% confidence interval (CI): 0.7-19.7%) and 53.3% (95% CI: 37.9-68.3%) with the highest prevalence observed in Ouangolodougou in the North. Cattle from farms had a relatively low prevalence of schistosomiasis, with the highest prevalence found in Ouangolodougou (2.4%, 95% CI: 0.7-6.1%). The prevalence of fascioliasis varied considerably from one department to another, ranging from nil (95% CI: 0.0-18.5%) to 50.8% (95% CI: 43.4-58.2%), with the highest prevalence found in farm cattle in Dikodougou in the North. Sheep and goats had a lower prevalence of schistosomiasis and fascioliasis than cattle. In slaughtered animals, cattle aged 4 years and older were at highest risk for schistosomiasis (odds ratio (OR): 2.4; 95% CI: 1.0-5.6) and fascioliasis (OR: 2.1; 95% CI: 1.1-3.9). In farm animals, male cattle had higher odds of being infected with Schistosoma (OR: 4.3; 95% CI: 0.7-26.9) than females. CONCLUSIONS: Our study confirms that schistosomiasis and fascioliasis are endemic in livestock across Cote d'Ivoire. A strategic control programme should be considered, especially for cattle, including providing drinking water in troughs to reduce faecal contamination of water sources by cattle