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

Research on the technics of round bosse sculpture at Carthage from Augustus to Constantin

Mes recherches portent sur les techniques de sculptures en ronde bosse d’époque romaine à Carthage. Pour mener ma recherche doctorale, j’ai rassemblé un corpus d’œuvres établi selon la production en ronde bosse, statues en pied et effigies abrégées en marbre. Il s’agit d’une collection de sculptures assez riche, qui s'est accru depuis la fin du XIXème siècle à travers des découvertes isolées et à partir du début du XXème siècle par le moyen de fouilles systématiques. Le choix d’une période aussi longue permet de poser la question d’une tradition technique éventuelle dans la production de la plastique en marbre ; le cas échéant, en relation avec l’histoire même de cette province d’Afrique du Nord. Toutefois, ni les fouilles ni le matériel étudié n’ont pu attester d’un lieu de production à Carthage. Néanmoins, le matériel réuni illustre un savoir-faire d’artisans locaux qui maitrisent les techniques d’exécution de sculptures. La mise en évidence de ces techniques nous ont permis d'entrevoir, les coulisses de cette production et de pouvoir apprécier ses procédés et de comprendre le degré de sa complexité.My research focuses on sculpture techniques in the round from the Roman period in Carthage. To conduct my doctoral research, I gathered a body of work established according to production in the round, full-length statues and abbreviated marble effigies. This is a fairly rich collection of sculptures, which has accumulated since the end of the 19th century through isolated discoveries and from the beginning of the 20th century through systematic excavations.The choice of such a long period raises the question of a possible technical tradition in the production of marble plastic; where appropriate, in relation to the very history of this provinceof North Africa. However, neither the excavations nor the material could attest to a place of production in Carthage. Nevertheless, the gathered material illustrates a know-how of local craftsmen who master the techniques of execution of sculptures. The highlighting of these techniques allowed us to glimpse behind the scenes of this production and to be able to appreciate its processes and to understand the degree of its complexity

Un atelier de copistes à Thuburbo Maius au iie siècle ap. J.-C.

Cette recherche s’inscrit dans le domaine de l’histoire des techniques : son but est de montrer comment les provinciaux de l’Afrique du Nord travaillaient la pierre à l’époque romaine. Le métier des sculpteurs en Proconsulaire est lié à des ateliers aussi bien permanents qu’itinérants. L’atelier de sculpture de Thuburbo Maius possédait ses propres sculpteurs. Cet atelier, qui a été converti en atelier de copistes au iie siècle ap. J.-C., a développé ses propres types et modèles iconographiques. L’analyse des procédés de fabrication montre à quel point les sculpteurs africains se sont adaptés à des situations variées dans une province aussi importante que la province romaine d’Afrique.This research is in the field of the history of technology which aims to show how the North African provincial sculpture worked in Roman times. The job of the sculptors in Proconsularis related workshops as well permanent and mobile. The sculpture studio of Thuburbo Maius had its own sculptors. This workshop, which was converted into workshop copyists in the second century AD, has developed the types and North African iconography models. Analysis of manufacturing processes shows how African sculptors have adapted to various situations in a province as large as the Roman province of Africa.Diese Untersuchung befasst sich mit der Geschichte der Technik : ihr Ziel ist es zu zeigen, mit welchen Methoden die Steinmetze der Provinz Africa in römischer Zeit arbeiteten. Der Beruf des Steinmetzes wurde sowohl in Wanderwerkstätten als auch in fest ansässigen Werkstätten ausgeübt. Die Bildhauerwerkstatt von Thuburbo Maius beschäftigte ihre eigenen Bildhauer. Diese Werkstatt, die die sich im 2. Jh. n. Chr. auf Kopien spezialisierte, hatte ihre eignen ikonographischen Typen und Modelle entwickelt. Die Analyse der Herstellungstechniken zeigt, in welchem Maße die Bildhauer sich in einer so bedeutenden Provinz wie der römischen Provinz Africa unterschiedlichen Situationen angepasst haben

A Dual-Band Printed Dipole Antenna for IMT-2000 and 5-GHz WLAN Wireless Applications

International audienc

Dual band printed dipole antenna for IMT 2000 and 5 GHz WLAN applications

International audienc

A dual-band printed dipole antenna for Imt-2000 and 5-GHz Wlan applications

International audienc

A dual-band printed dipole antenna for Imt-2000 and 5-GHz Wlan applications

International audienc

Design of a printed Elliptic Reconfigurable Dual Band-rejected UWB Micro-strip Fed Antenna

International audienc

A Planar Reconfigurable Radiation Pattern Dipole Antenna with Reflectors and Directors for Wireless Communication Applications

International audienceA planar printed dipole antenna with reflectors and directors, able to steer its radiation pattern in different directions, is proposed for telecommunication applications. Starting from a dual-beam printed dipole antenna achieved by combining two elementary dipoles back to back, and by loading four PIN diodes, three modes of reconfigurable radiation patterns are achieved at the frequency 2.56 GHz thanks to switches states. A prototype of the structure was realized and characterized; an efficiency of 75% is obtained. Simulation and measured results of the results are presented and discussed

Planar Square Multiband Frequency Reconfigurable Micro-strip Fed Antenna with Quadratic Koch-Island Fractal Slot for Wireless Devices

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