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

Neuro-fuzzy controller for autonomous navigation of mobile robots

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Compact bionic handling arm control using neural networks

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Adaptive navigation of an omni-drive autonomous mobile robot in unstructured dynamic environments

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Neural Networks based approach for inverse kinematic modeling of a Compact Bionic Handling Assistant trunk

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Qualitative approach for forward kinematic modeling of a Compact Bionic Handling Assistant trunk

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Oscillator strengths, transition probabilities and state lifetimes of on- and off-center donor impurities in quantum dots: off-center displacement, quantum size and potential-shape effects

Nonrelativistic dipole matrix elements, oscillator strengths, transition probabilities and states lifetimes of quantum dots with centered and off-centered hydrogenic impurities are studied. The effects of the off-center displacement combined to the shape of the confining potential are investigated. These optical parameters are found to be strongly modified by the parameters characterizing the confinement as well as by taking into account of the off-center shift. It is found that the oscillator strengths present a minimum for certain values of the confinement potential range and of the off-center displacement, principally due to the reaching of a low energy gap between the levels involved in the concerned transition. Likewise, the states lifetimes increase with the off-center displacement whatever the shape of the confinement potential is because of the reduction of the gap between the energies of the states when the displacement is no longer equal to zero

Qualitative approach for inverse kinematic modeling of a Compact Bionic Handling Assistant trunk

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Forward Kinematic Modeling of Conical-Shaped Continuum Manipulators

International audienceSUMMARY Forward kinematics is essential in robot control. Its resolution remains a challenge for continuum manipulators because of their inherent flexibility. Learning-based approaches allow obtaining accurate models. However, they suffer from the explosion of the learning database that wears down the manipulator during data collection. This paper proposes an approach that combines the model and learning-based approaches. The learning database is derived from analytical equations to prevent the robot from operating for long periods. The database obtained is handled using Deep Neural Networks (DNNs). The Compact Bionic Handling robot serves as an experimental platform. The comparison with existing approaches gives satisfaction