20 research outputs found
Effets du compost enrichi de l’urine humaine sur le rendement de la pomme de terre (MANDOLA) dans la Commune Urbaine de Faranah/République de Guinée
Le faible niveau d’apport des engrais minéraux par les producteurs dus son prix exorbitant est l’un des facteurs limitant la production de la pomme de terre. Le compost enrichi de l’urine constitue une alternative pour augmenter le rendement des cultures à faible coût. L’objectif principal de ce travail était d’évaluer l’effet des doses du compost enrichi de l’urine humaine sur le rendement de la pomme de terre (MANDOLA). Les doses du compost enrichi par l’urine humaine utilisées sont : D0=0t/ha (Témoin) ; D1=15t /ha (240g /poquet) ; D2=30t /ha (480g/poquet) ; D3= 45t /ha (720g/poquet). Les résultats de l’observation phénologique ont montré que les différentes doses appliquées ont eu un effet en réduisant le cycle végétatif de la culture D1 (72 jours), D2 et D3 (70 jours) contre D0 (74 jours). Au vu des résultats d’analyse de variance, le rendement total en tubercules la dose D3 (13,07 t /ha) a été meilleure, suivie de D2 (12,76 t/ha) et D1 (11,98 t/ha) ; le plus faible rendement a été obtenu au niveau du témoin D0 (10,16t/ha). Cela dénote que l’apport du compost enrichi de l’urine humaine contribue à l’augmentation du rendement de la pomme terre
Annual population dynamics of mango fruit flies (Diptera: Tephritidae) in West Africa: Socio-economic aspects, host phenology and implications for management
Losses in West African commercial mango orchards due to fruit fly infestations have exceeded 50% by the middle of the crop season since 2005, resulting in considerable income loss for the growers. Materials and methods. In 2009, weekly monitoring of adult fruit fly species of economic significance was carried out in eight West African countries at 12 sites across five agro-ecological zones: (i) Humid Forest, (ii) Guinean savanna, (iii) Southern Sudan, (iv) Northern Sudan, and (v) Sahelian. Trapping was performed using methyl eugenol and terpinyl acetate in 288 Tephritraps, targeting Bactrocera invadens and Ceratitis cosyra. Results. The data showed that B. Invadens was present throughout the year in the Forest zone, abundant for 7 months, with a peak in May at the end of the mango season, C. cosyra being totally absent. In the Guinean savanna zone, B. invadens was abundant for 6-7 months, with a peak at the beginning of June coinciding with the season, with a few C. cosyra. In the Southern Sudan zone, B. invadens was abundant for 6 months, with a peak in mid-June during the season, C. cosyra peaking in April. In the Northern Sudan zone, B. invadens was abundant for 5 months, with a peak at the end of June at the end of the season, C. cosyra peaking in May. In the Sahelian zone, B. invadens was abundant for 4 months, peaking in August during the sea-son, C. cosyra peaking just before. These preliminary results showed that the exotic species, B. invadens, was present at high levels [mean peak of 378 flies per trap per day (FTD)] in all agro-eco-logical zones, while the native species, C. cosyra, preferred the drier zones of West Africa, with lower population levels (mean peak of 77 FTD).Conclusion. Detection trapping of male flies with parapheromones is a useful indicator of field population levels and could be used to deploy control measures (IPM package) in a timely manner when the Economic Injury Level is reached. Control strategies for these quarantine mango fruit fly species are discussed with respect to agro-ecological zones and the phenological stages of the mango tree. (Résumé d'auteur
L'Afrique noire est bien partie. [2], Le Tribalisme ne passera pas / Lanciné Camara
Contient une table des matièresAvec mode text
Evaluation of the Efficacy of Castor Oil as a Biopesticide in the Treatment of Leucinodes orbitalis Guenee L., A Pest of Eggplant (Solanum melongena)
Leucinodes orbonalis Guenée L. is a pest of Aubergine. It is currently managed using synthetic chemical pesticides. However, certain plants with insecticidal properties can be used to control Leucinodes orbonalis in aubergines. To study the effectiveness of the castor oil solution, a trial was carried out at the ISAV in Faranah from 08/05 to 20/08/2023. Castor oil was extracted using a press machine with a yield of 0.41 l/kg. Under field conditions, the study involved 80 aubergine plants. The parameters monitored were: incidence of attack, number of plants leafed out and productivity. The survival of Leucinodes orbonalis larvae after treatment was also estimated in vitro. The doses used were: D0 = 0 l/ha (control); D1 = 2.5 l/ha; D2 = 5 l/ha and D3 = 7.5 l/ha. The results showed that the incidence of attack after treatment was 68% for the control. However, this incidence was 10, 4 and 2% respectively for doses D1, D2 and D3. With regard to the number of plants thinned out, the rates were 68% for the control, 33% for D1, 17% for D2 and 8% for D3. Productivity was: 3.0 t/ha for the control; 5 t/ha for D1; 8 t/ha for D2 and 11.02 t/ha for D3. Survival of Leucinodes orbonalis larvae after application of the castor oil solution was 92%, 20%, 10% and 0% respectively for the D1, D2 and D3 controls. Analysis of the results shows that the 7.5 l/ha dose of castor oil is a good biopesticide for controlling Leucinodes orbonalis
Reversible Fragile Watermarking Scheme for Relational Database Based on Prediction-Error Expansion
The protection of database systems content using digital watermarking is nowadays an emerging research direction in information security. In the literature, many solutions have been proposed either for copyright protection and ownership proofing or integrity checking and tamper localization. Nevertheless, most of them are distortion embedding based as they introduce permanent errors into the cover data during the encoding process, which inevitably affect data quality and usability. Since such distortions are not tolerated in many applications, including banking, medical, and military data, reversible watermarking, primarily designed for multimedia content, has been extended to relational databases. In this article, we propose a novel prediction-error expansion based on reversible watermarking strategy, which not only detects and localizes malicious modifications but also recovers back the original data at watermark detection. The effectiveness of the proposed method is proved through rigorous theoretical analysis and detailed experiments
Vers une lutte contre la cercosporiose des agrumes en Guinée
Introduction. L'apparition de la cercosporiose due à Phaeoramularia angolensis en 1993 en Guinée constitue de nos jours l'un des facteurs limitants de la culture des agrumes dans ce pays. Le manque de connaissance sur la sensibilité, vis-à -vis du pathogène, des espèces ou variétés d'agrumes présentes localement freine la relance projetée pour cette culture. Face à cet enjeu, des études sur la sensibilité in situ et des essais de contrôle chimique de la maladie ont été entrepris. Matériel et méthodes. Des agrumes en collections et en plantations villageoises ont été suivis de 1995 à 1999 dans les principales régions productrices d'agrumes de Guinée afin d'évaluer la sensibilité à Phaeoramularia angolensis d'une soixantaine de variétés. En complément, un essai de lutte chimique a été mené en 1999 afin de définir les doses et fréquences de traitements à recommander aux planteurs pour contrôler la maladie. Le taux d'organes atteints et les pertes de production dues au pathogène ont été évalués. Résultats et discussion. Les sensibilités ont varié suivant les sites mais surtout en fonction des espèces et de leurs variétés. Presque tous les orangers et tous les tangelos et pomelos se sont montrés sensibles à très sensibles à la maladie avec des taux de dépréciations de l'ensemble de la production (feuilles et fruits) souvent supérieurs à 30 %. Les taux de sensibilité des mandariniers ont été plus contrastés avec des variétés tolérantes (Ponkan) à très sensibles (Hansen). Les tangors, citronniers, limettiers, kumquats et pamplemoussiers se sont révélés tolérants dans tous les sites à la seule exception du limettier Tahiti et du citronnier Meyer au-dessus de 800 m d'altitude. Lors de l'essai de lutte chimique, la dose de 100 g de matière active 100 L-1 d'eau appliquée tous les 10 j a permis d'élever en moyenne à près de 90 % le taux de fruits potentiellement commercialisables. Par ailleurs, la rentabilité des vergers a décru rapidement dès que le taux d'attaques des fruits a été supérieur à 20 %. Conclusion. Nos résultats montrent que de nouvelles recherches entreprises dans le contexte actuel de l'agrumiculture guinéenne pourraient permettre de répondre aux problèmes de stratégies de lutte à adopter, de produits, doses ou périodes à recommander et de variétés à promouvoir dans le pays
Correction: Experimental Treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial): A Historically Controlled, Single-Arm Proof-of-Concept Trial in Guinea.
[This corrects the article DOI: 10.1371/journal.pmed.1001967.]
Experimental treatment with Favipiravir for Ebola Virus Disease (the JIKI Trial) : a historically controlled, single-arm proof-of-concept trial in Guinea
BACKGROUND:Ebola virus disease (EVD) is a highly lethal condition for which no specific treatment has proven efficacy. In September 2014, while the Ebola outbreak was at its peak, the World Health Organization released a short list of drugs suitable for EVD research. Favipiravir, an antiviral developed for the treatment of severe influenza, was one of these. In late 2014, the conditions for starting a randomized Ebola trial were not fulfilled for two reasons. One was the perception that, given the high number of patients presenting simultaneously and the very high mortality rate of the disease, it was ethically unacceptable to allocate patients from within the same family or village to receive or not receive an experimental drug, using a randomization process impossible to understand by very sick patients. The other was that, in the context of rumors and distrust of Ebola treatment centers, using a randomized design at the outset might lead even more patients to refuse to seek care. Therefore, we chose to conduct a multicenter non-randomized trial, in which all patients would receive favipiravir along with standardized care. The objectives of the trial were to test the feasibility and acceptability of an emergency trial in the context of a large Ebola outbreak, and to collect data on the safety and effectiveness of favipiravir in reducing mortality and viral load in patients with EVD. The trial was not aimed at directly informing future guidelines on Ebola treatment but at quickly gathering standardized preliminary data to optimize the design of future studies.METHODS AND FINDINGS:Inclusion criteria were positive Ebola virus reverse transcription PCR (RT-PCR) test, age ≥ 1 y, weight ≥ 10 kg, ability to take oral drugs, and informed consent. All participants received oral favipiravir (day 0: 6,000 mg; day 1 to day 9: 2,400 mg/d). Semi-quantitative Ebola virus RT-PCR (results expressed in "cycle threshold" [Ct]) and biochemistry tests were performed at day 0, day 2, day 4, end of symptoms, day 14, and day 30. Frozen samples were shipped to a reference biosafety level 4 laboratory for RNA viral load measurement using a quantitative reference technique (genome copies/milliliter). Outcomes were mortality, viral load evolution, and adverse events. The analysis was stratified by age and Ct value. A "target value" of mortality was defined a priori for each stratum, to guide the interpretation of interim and final analysis. Between 17 December 2014 and 8 April 2015, 126 patients were included, of whom 111 were analyzed (adults and adolescents, ≥13 y, n = 99; young children, ≤6 y, n = 12). Here we present the results obtained in the 99 adults and adolescents. Of these, 55 had a baseline Ct value ≥ 20 (Group A Ct ≥ 20), and 44 had a baseline Ct value < 20 (Group A Ct < 20). Ct values and RNA viral loads were well correlated, with Ct = 20 corresponding to RNA viral load = 7.7 log10 genome copies/ml. Mortality was 20% (95% CI 11.6%-32.4%) in Group A Ct ≥ 20 and 91% (95% CI 78.8%-91.1%) in Group A Ct < 20. Both mortality 95% CIs included the predefined target value (30% and 85%, respectively). Baseline serum creatinine was ≥110 μmol/l in 48% of patients in Group A Ct ≥ 20 (≥300 μmol/l in 14%) and in 90% of patients in Group A Ct < 20 (≥300 μmol/l in 44%). In Group A Ct ≥ 20, 17% of patients with baseline creatinine ≥110 μmol/l died, versus 97% in Group A Ct < 20. In patients who survived, the mean decrease in viral load was 0.33 log10 copies/ml per day of follow-up. RNA viral load values and mortality were not significantly different between adults starting favipiravir within <72 h of symptoms compared to others. Favipiravir was well tolerated.CONCLUSIONS:In the context of an outbreak at its peak, with crowded care centers, randomizing patients to receive either standard care or standard care plus an experimental drug was not felt to be appropriate. We did a non-randomized trial. This trial reaches nuanced conclusions. On the one hand, we do not conclude on the efficacy of the drug, and our conclusions on tolerance, although encouraging, are not as firm as they could have been if we had used randomization. On the other hand, we learned about how to quickly set up and run an Ebola trial, in close relationship with the community and non-governmental organizations; we integrated research into care so that it improved care; and we generated knowledge on EVD that is useful to further research. Our data illustrate the frequency of renal dysfunction and the powerful prognostic value of low Ct values. They suggest that drug trials in EVD should systematically stratify analyses by baseline Ct value, as a surrogate of viral load. They also suggest that favipiravir monotherapy merits further study in patients with medium to high viremia, but not in those with very high viremia.TRIAL REGISTRATION:ClinicalTrials.gov NCT02329054.Evaluation of the efficacy and of the antiviral activity of T-705 (favipiravir) duringEbola virus infection in non-human primates humansEbola Virus Disease - correlates of protection, determinants of outcome, and clinical managemen