Gestion intégrée de Maruca vitrata (FABRICIUS, 1787) et Megalurothrips sjostedti (TRYBOM, 1908), deux insectes ravageurs majeurs du niébé au Niger

Le niébé, Vigna unguiculata (L.) Walp. est la principale légumineuse cultivée au Niger. C’est une culture d’importance économique, sociale et alimentaire. Sa productivité est faible eu égard entre autres à la forte pression des bioagresseurs. La gestion intégrée des ravageurs est l’une des stratégies adoptées pour accroître la productivité du niébé. L’objectif de l’étude est de proposer un système de gestion intégrée de Maruca vitrata et de Megalurothrips sjostedti, principaux ravageurs du niébé au Niger. L’essai est conduit sur deux différentes variétés du niébé: la TN5-78 et la KVX908-1. Le dispositif expérimental utilisé est un split plot avec quatre traitements et quatre répétitions. Le résultat du suivi des effectifs des deux insectes a montré une prédominance de Megalurothrips sjostedti par rapport à Maruca vitrata sur la TN5-78 (607,25 et 15,25 individus, respectivement). Il en est de même sur la KVX908-1, avec respectivement 307,25 et 17,5 individus. La comparaison de la densité des populations des ravageurs étudiés, montre qu’elle est plus faible dans les parcelles traitées au Super-Diforce par rapport aux parcelles traitées avec le Neem et la préparation virale (MaviNPV). Dans l’ensemble, le dispositif permet de réduire de façon significative la densité de Maruca vitrata et de Megalurothrips sjostedti. L’efficacité de la stratégie se traduit par l’obtention des rendements de 1,02 à 2,169 t/ha pour la variété TN5-78 et 1,96 à 3,06t/ha pour la KVX908-1.Mots clés : Lutte intégrée, Maruca vitrata, Megalurothrips sjostedti, Vigna unguiculata, MaviNPV, Neem, insecticide chimiqu

Air-clad suspended nanocrystalline diamond ridge waveguides

A hybrid group IV ridge waveguide platform is demonstrated, with potential application across the optical spectrum from ultraviolet to the far infrared wavelengths. The waveguides are fabricated by partial etching of sub-micron ridges in a nanocrystalline diamond thin film grown on top of a silicon wafer. To create vertical confinement, the diamond film is locally undercut by exposing the chip to an isotropic fluorine plasma etch via etch holes surrounding the waveguides, resulting in a mechanically stable suspended air-clad waveguide platform. Optical characterization of the waveguides at 1550 nm yields an average optical loss of 4.67 ± 0.47 dB/mm. Further improvement to the fabrication process is expected to significantly reduce this waveguide loss

Transport and Deposition of Saharan Dust Observed from Satellite Images and Ground Measurements

Haboob occurrence strongly impacts the annual variability of airborne desert dust in North Africa. In fact, more dust is raised from erodible surfaces in the early summer (monsoon) season when deep convective storms are common but soil moisture and vegetation cover are low. On 27 June 2018, a large dust storm is initiated over North Africa associated with an intensive westward dust transport. Far away from emission sources, dust is transported over the Atlantic for the long distance. Dust plume is emitted by a strong surface wind and further becomes a type of haboob when it merges with the southwestward deep convective system in central Mali at 0200 UTC (27 June). We use satellite observations to describe and estimate the dust mass concentration during the event. Approximately 93% of emitted dust is removed the dry deposition from the atmosphere between sources (10°N–25°N; 1°W–8°E) and the African coast (6°N–21°N; 16°W–10°W). The convective cold pool has induced large economic and healthy damages, and death of animals in the northeastern side of Senegal. ERA5 reanalysis has shown that the convective mesoscale impacts strongly the climatological location of the Saharan heat low (SHL)

Short-term forecasting of the prevalence of clinical trachoma: utility of including delayed recovery and tests for infection.

BACKGROUND: The World Health Organization aims to control blinding trachoma by 2020. Decisions on whether to start and stop mass treatments and when to declare that control has been achieved are currently based on clinical examination data generated in population-based surveys. Thresholds are based on the district-level prevalence of trachomatous inflammation-follicular (TF) in children aged 1-9 years. Forecasts of which districts may and may not meet TF control goals by the 2020 target date could affect resource allocation in the next few years. METHODS: We constructed a hidden Markov model fit to the prevalence of two clinical signs of trachoma and PCR data in 24 communities from the recent PRET-Niger trial. The prevalence of TF in children in each community at 36 months was forecast given data from earlier time points. Forecasts were scored by the likelihood of the observed results. We assessed whether use of TF with additional TI and PCR data rather than just the use of TF alone improves forecasts, and separately whether incorporating a delay in TF recovery is beneficial. RESULTS: Including TI and PCR data did not significantly improve forecasts of TF. Forecasts of TF prevalence at 36 months by the model with the delay in TF recovery were significantly better than forecasts by the model without the delay in TF recovery (p = 0.003). A zero-inflated truncated normal observation model was better than a truncated normal observation model, and better than a sensitivity-specificity observation model. CONCLUSION: The results in this study suggest that future studies could consider using just TF data for forecasting, and should include a delay in TF recovery. TRIAL REGISTRATION: Clinicaltrials.gov NCT00792922

Choriocarcinoma on hysterectomy specimen in Senegal: histological study

Background: Trophoblastic diseases are in general exclusive to women in their reproductive years. Gestational choriocarcinoma (GC) is a rare malignant tumor derived from the trophoblast of women in childbearing age. Our objective was to study the epidemiological and clinicopathologic aspects at the laboratories of pathological anatomy and cytology (ACP) of Aristide Le Dantec Hospital and General Idrissa Pouye Hospital.Methods: Our study was conducted in the anatomy and pathology laboratories of the Hôpital Général Idrissa Pouye and the Hôpital Aristide Le Dantec in Dakar. This study was based on records of pathological reports of gestational choriocarcinomas from these different laboratories. This was a retrospective and descriptive bi-centric study, spread over eight (8) years from January 1, 2013, to December 31, 2020. All cases diagnosed on hysterectomy specimens and with a formal conclusion of choriocarcinoma have been included. We recorded the data collected in Excel 2007 software and the analysis was made using Epi Info.Results: We collected 25 cases of choriocarcinomas. The mean age of the patients was 38.1±9.7. Mixed seat tumors (intra-cavitary and intra-mural) were the most frequent with 48% of cases. Patients who were at FIGO stage 1 represented for 88% of cases.Conclusions: Gestational choriocarcinoma (GC) is a proliferation of the trophoblast (cytotrophoblast and syncitiotrophoblast). This study has helped establish histopathological data of choriocarcinoma on hysterectomy specimen in Dakar