Modeling and Solving a Linear Integer Problem (PLNE) for the Optimal Localization of a Hub Air Transport in the WAEMU Zone

In this article, we propose a linear integer model for the optimal location of a hub for air traffic in the WAEMU zone. A hub represents for an airline a base where an essential part of its activities is concentrated. Its location must therefore be judiciously determined. The hub location problem is one of the new and promising areas of research in the field of location theory. In order to satisfy a demand, the location of the hub involves the movement of people, goods between origin destination pairs required. Hubs are applied to reduce the number of transport links between the origin and destination airports The proposed model minimizes the distances and takes into account the flow of passengers registered in the different airports and minimizes the total cost of the transfer via the hub airport. The simulations were made with the programming language Python

Modeling and Solving a Linear Integer Problem (PLNE) for the Optimal Localization of a Hub Air Transport in the WAEMU Zone

In this article, we propose a linear integer model for the optimal location of a hub for air traffic in the WAEMU zone. A hub represents for an airline a base where an essential part of its activities is concentrated. Its location must therefore be judiciously determined. The hub location problem is one of the new and promising areas of research in the field of location theory. In order to satisfy a demand, the location of the hub involves the movement of people, goods between origin destination pairs required. Hubs are applied to reduce the number of transport links between the origin and destination airports. The proposed model minimizes the distances and takes into account the flow of passengers registered in the different airports and minimizes the total cost of the transfer via the hub airport. The simulations were made with the programming language Python

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Characterization of the swarming behavior of Anopheles coluzzii and Anopheles gambiae (Diptera: Culicidae) populations in a hybrid zone of Senegal.

Anopheles gambiae and Anopheles coluzzii, often found in sympatry and synchronous, have undergone a premating reproductive isolation across their distribution range. However, in the Western coast of Africa, unexpected hybridization zones have been observed, and little is known about swarming behavior of these cryptic taxa. Here, we characterized the swarming behavior of An. coluzzii and An. gambiae to investigate its role in the high hybridization level in Senegal. The study was conducted in the south and central Senegal during the 2018 rainy season. Mating swarms of malaria vectors were surveyed at sunset and collected using an insect net. Meanwhile, indoor resting populations of malaria vectors were collected by pyrethrum spray catches. Upon collection, specimens were identified morphologically, and then members of the An. gambiae complex were identified at the species level by polymerase chain reaction (PCR). An. gambiae swarmed mainly over bare ground, whereas An. coluzzii were found swarming above various objects creating a dark-light contrast with the bare ground. The swarms height varied from 0.5 to 2.5 m. Swarming starting time was correlated with sunset whatever the months for both species, and generally lasted about 10 min. No mixed swarm of An. gambiae and An. coluzzii was found even in the high hybridization area. These results indicated a premating isolation between An. coluzzii and An. gambiae. However, the high hybridization rate in the sympatric area suggests that heterogamous mating is occurring, thus stressing the need for further extensive studies. [Abstract copyright: © The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: [email protected].

Le projet majeur africain de la Grande Muraille Verte

L’initiative de la Grande Muraille Verte (GMV), projet transcontinental, est une réponse de l’Afrique à la désertification, à la pauvreté et au changement climatique. Elle repose sur une approche concertée, multisectorielle, mettant en synergie des actions de lutte contre ces trois fléaux majeurs pour le continent africain. La particularité de la GMV est, tout en créant et consolidant une ligne de défense par des activités de reboisement et d’aménagement, de contribuer efficacement au développement intégré des zones rurales et d’aider à la lutte contre la pauvreté dans le cadre d’un développement durable. Il s’agit de l’installation et de la mise en valeur intégrée d’espèces végétales à valeur économique adaptées aux terres arides et aux particularités locales, de bassins de rétention, de systèmes de production agricoles et autres activités génératrices de revenus. La GMV intègre ainsi plusieurs systèmes des plantations artificielles anciennes ou nouvelles, des unités agro-sylvo-pastorales. Des zones de parcours villageoises ou intercommunautaires, des parcs animaliers, des réserves communautaires et des couloirs de migration de faune. Cet édifice transcontinental est une référence de modèle d’intégration sous-régional mettant en exergue une initiative originale initiée par des pays fortement assujettis aux phénomènes de désertification et de changement climatique Il constitue un Modèle Multisectoriel de Développement Intégré des Zones Andes (MDI/ZA). Dédié à la lutte contre tes effets et l’avancée de la désertification, à la restauration et la mise en valeur des zones dégradées et au mécanisme de développement propre dû à sa forte capacité de séquestration de carbone. L’ouvrage vise un large public, notamment les scientifiques, enseignants, décideurs, techniciens charges de la mise en œuvre de la GMV et permet d’apprécier l’originalité du projet dans son approche concertée et multisectorielle et ses résultats dans le développement intégré des zones arides a semi-arides

Ebola Virus Transmission Initiated by Relapse of Systemic Ebola Virus Disease

During the 2018-2020 Ebola virus disease (EVD) outbreak in North Kivu province in the Democratic Republic of Congo, EVD was diagnosed in a patient who had received the recombinant vesicular stomatitis virus-based vaccine expressing a ZEBOV glycoprotein (rVSV-ZEBOV) (Merck). His treatment included an Ebola virus (EBOV)-specific monoclonal antibody (mAb114), and he recovered within 14 days. However, 6 months later, he presented again with severe EVD-like illness and EBOV viremia, and he died. We initiated epidemiologic and genomic investigations that showed that the patient had had a relapse of acute EVD that led to a transmission chain resulting in 91 cases across six health zones over 4 months. (Funded by the Bill and Melinda Gates Foundation and others.)

Abstracts of the 1st International Colloquium in Mine & Society

This book presents the abstracts of the selected contributions to the First International Colloquium on Mines and Society (CIMS) organized by The Higher Institute of Mining and Geology of Boke. The theme of this colloquium was "Mining and Sustainable Development, a major challenge for an Emerging Africa" which aims to bring together teachers, researchers, and Professionals from different backgrounds in order to exchange the results of their research work, share their points of view on the issue of mining and sustainable development. It also aims to define, in a collaborative and inclusive manner, research prospects or future projects between all the actors involved in this field. Colloquium Title: 1st International Colloquium in Mine & SocietyTheme: Mining and Sustainable Development, A Major Challenge for an Emerging AfricaColloquium Date: 20-22 May 2022Colloquium Location: A L’Hôtel Rio Nunez de BokeColloquium Organizer: The Higher Institute of Mining and Geology of Bok