Serological, molecular characterization and epidemiological situation of equine influenza in the Arabic Maghreb countries between 1972 to 2010

AbstractEquine influenza is an infectious and contagious disease of horses. Studies on this topic are rare in the Maghreb countries. Therefore, the aim of this work is to present the various studies conducted on serological and molecular equine influenza virus since 1972 in the Maghreb region in particular in Morocco, Algeria and Tunisia.A total of four equine influenza strains were isolated in the Maghreb Arab region. A/equine/Nador/1/1997(H3N8), A/equine/Essaouira/2/2004(H3N8), A/equine/Essaouira/3/2004(H3N8) and A/equine/Algiers/1/1972(H3N8).The highest homology of HA nucleotide sequences of A/equine/Nador/1/1997(H3N8) with European strains: A/equine/Italy/1199/1992(H3N8) and A/equine/Brescia/1999(H3N8) clearly clustered A/equine/Nador/1/1997(H3N8) with the strains belonging to the European lineage. However, A/equine/Algiers/1/1972(H3N8), A/equine/Essaouira/2/2004(H3N8) and A/equine/Essaouira/3/2004(H3N8) were placed in the predivergent lineage indicating that like-Miami/63 strains infected equids in Morocco in 2004.This finding does not corroborate the recent studies of the H3N8 subtype of equine influenza viruses which have demonstrated that the oldest equine H3N8 strains, circulating before 1990 apparently went extinct

Evolutions and threats to land management in the peri-urban area of the city of Sidi Bel Abbes (Algeria) - an analysis based on spatial cadastral data

Sidi Bel Abbes, the capital of Mekerra, a city of the interior plain, where agricultural land has experienced urban spillover at the expense of peri-urban land. The accelerated sprawl between 1987 and 2019 is expressed by threats to peri-urban state land, the pressure on agricultural activity on the peripheries of the city, and a relaxation of respect for planning policies at the local level. How can peri-urban land be better protected, and consequently encourage agricul-tural use, without abandoning it? This work analyses the legal nature of the land taken for the benefit of urban construction and characterizes its spread using Landsat multispectral satellite data. Our approach is based on the following question: Does urban sprawl impact the man-agement of land and its legal nature? What is the future of this land in the face of current threats and future planning and urban development orientations? The cartographic analyses with the actual practices of the different social groups in the field have made it possible to evaluate the relationship between agricultural policy, and implementation and to situate the conflicts or threats about urban sprawl. The north of the city of Sidi Bel Abbes (cadastral sec-tion n°3, 324.74 ha), is where 45% of state land is acquired for building purposes. A reorienta-tion of the peri-urban land is currently presented by a new management mode of an individual type, as a means of freezing and/or preserving the land: the creation of hedges and fences, the introduction of arboriculture (olive tree or other). Observations on site made it possible to ex-plain these practices, which are at the origin of these current representations. The crops prac-tice is linked to the profit drawn on compensations, and the plantations are a source of good remuneration

Ex vivo effects of flavonoïds extracted from Artemisia herba alba on cytokines and nitric oxide production in Algerian patients with Adamantiades-Behçet's disease

<p>Abstract</p> <p>Background</p> <p>Adamantiades-Behçet's disease (ABD) is a chronic multisystemic inflammation with unknown pathophysiology. This disorder is associated with a dysregulation of the cytokine network that hyperactivates neutrophils and macrophages. In this study, we investigate the modulatory effects of flavonoïd compounds extracted from Algerian medicinal plant <it>Artemisia herba alba </it>on Th1 and Th2 cytokines and nitric oxide production.</p> <p>Methods</p> <p>The modulatory effects of flavonoïds extracted from <it>Artemisia herba alba </it>on cytokines and nitric oxide production by peripheral blood mononuclear cells isolated from Algerian ABD patients and healthy controls were respectively measured by means of ELISA assays and Griess modified method.</p> <p>Results</p> <p>Our results show that flavonoïds significantly reduce the production of interleukin-12, the key effector of T helper 1 (Th1) cells and nitric oxide in a dose-dependent manner in Adamantiades-Behçet's disease. In contrast, the production of IL-4, the key marker of Th2 cells was increased.</p> <p>Conclusion</p> <p>This study suggests that <it>in vitro </it>supplementation with flavonoïds extracted from <it>Artemisia herba alba </it>could have potential immuno-modulatory effects characterised by a down-regulation and up-regulation of Th1 and Th2 cytokines, respectively. Moreover, flavonoïds may prevent nitric oxide induced damages.</p

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa.

The progression of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in Africa has so far been heterogeneous, and the full impact is not yet well understood. In this study, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations predominantly from Europe, which diminished after the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1, and C.1.1. Although distorted by low sampling numbers and blind spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a source for new variants

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

Mesures en temps réel de phénomènes ultra-courts : applications aux oscillateurs laser et à la métrologie optique

This PhD work is mainly focused on the development of efficient measurement tools for the study of the ultrafast dynamics of various physical phenomena, from those occurring within laser oscillators to laser-matter interactions. The manuscript is separated between interrelated studies dealing with laser physics, ablation dynamics and ultrafast metrology. This work is then partially devoted to the design and implementation of an efficient fiber optical parametric chirped pulse oscillator, where the well-known concept of fiber optical parametric oscillation (FOPO) is combined with the principle of chirped pulse amplification. This led to the efficient generation of high-energy, tunable, synchronized picosecond pulses in specific spectral regions. Simulations of this system has shown great potential in energy scaling and unveiled interesting dynamics. Such dynamics were then investigated using the dispersive Fourier transform technique, which enables the recording of shot-to-shot spectra and provides a large data sets for statistical analysis. This allowed for the energy tracking during the wavelength conversion process and resulted in a better comprehension of its dynamic behaviors. This work was then focused towards the development of a novel ultrafast imaging technique for studying the dynamics of several laser matter interaction processes including the optical Kerr effect, laser ablation and laser-induced air breakdown. An imaging system based on spectrally filtered sequentially timed all-optical mapping photography (SF-STAMP) together with acousto-optics filtering was developed and allowed to capture physical phenomena either in the picosecond or nanosecond time scale with a full control over the illumination conditions, exposure time and time between frames. The outcomes of this feasibility demonstration are manifold and could help to bring such ultrafast techniques out of a laboratory environment.Ce travail de doctorat est principalement axé sur le développement d’outils de mesure efficaces dédiés à l’étude des dynamiques ultrarapides de divers phénomènes physiques, des oscillateurs laser jusqu’aux interactions laser-matière. Le manuscrit est ainsi séparé en plusieurs études connexes traitant de la physique des lasers, des dynamiques mises en jeu lors de l’ablation laser et plus généralement de la métrologie ultrarapide. Ce travail est ensuite dans un premier temps consacré à la conception et à la mise en œuvre d’un oscillateur paramétrique fibré à impulsions chirpées innovant, où le concept bien connu d’oscillateur paramétrique à fibre optique (FOPO) est combiné au principe d’amplification à dérive de fréquence. Ce nouveau concept a permis de générer efficacement des impulsions picosecondes synchronisées, accordables et à haute énergie dans des régions spectrales d’intérêt. Les simulations numériques de ce système ont démontré un fort potentiel pour la montée en énergie mais aussi dévoilé des dynamiques intéressantes. Ces dynamiques ont ensuite été étudiées à l’aide de la technique de transformée de Fourier dispersive, qui permet d’enregistrer des spectres tir-à-tir et de fournir efficacement un grand nombre de données pour l’analyse statistique. Cela a permis de suivre les transferts d’énergie pendant les processus de conversion paramétriques et de mieux comprendre leurs dynamiques. Ce travail s’est ensuite orienté vers le développement d’une nouvelle technique d’imagerie ultrarapide pour étudier les dynamiques de plusieurs processus d’interaction laser-matière, notamment l’effet Kerr optique, l’ablation laser et le claquage dans l’air induit par laser. Un système d’imagerie basé sur la technique STAMP (sequentially timed all-optical mapping photography) combinée à une étape de filtrage acousto-optique a été développé et a permis de capturer des phénomènes physiques à l’échelle de la picoseconde ou de la nanoseconde avec un contrôle total des conditions d’illumination, du temps d’exposition et du temps entre les images. Les résultats de cette démonstration de faisabilité sont ainsi multiples et pourraient permettre l’utilisation de techniques d’imagerie ultra-rapide hors d’un environnement de laboratoire

LERMA : langage pour engins robotises multitaches et autonomes

SIGLECNRS T 56331 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Real time measurement of ultrafast phenomena : application to laser oscillators and optical metrology

Ce travail de doctorat est principalement axé sur le développement d’outils de mesure efficaces dédiés à l’étude des dynamiques ultrarapides de divers phénomènes physiques, des oscillateurs laser jusqu’aux interactions laser-matière. Le manuscrit est ainsi séparé en plusieurs études connexes traitant de la physique des lasers, des dynamiques mises en jeu lors de l’ablation laser et plus généralement de la métrologie ultrarapide. Ce travail est ensuite dans un premier temps consacré à la conception et à la mise en œuvre d’un oscillateur paramétrique fibré à impulsions chirpées innovant, où le concept bien connu d’oscillateur paramétrique à fibre optique (FOPO) est combiné au principe d’amplification à dérive de fréquence. Ce nouveau concept a permis de générer efficacement des impulsions picosecondes synchronisées, accordables et à haute énergie dans des régions spectrales d’intérêt. Les simulations numériques de ce système ont démontré un fort potentiel pour la montée en énergie mais aussi dévoilé des dynamiques intéressantes. Ces dynamiques ont ensuite été étudiées à l’aide de la technique de transformée de Fourier dispersive, qui permet d’enregistrer des spectres tir-à-tir et de fournir efficacement un grand nombre de données pour l’analyse statistique. Cela a permis de suivre les transferts d’énergie pendant les processus de conversion paramétriques et de mieux comprendre leurs dynamiques. Ce travail s’est ensuite orienté vers le développement d’une nouvelle technique d’imagerie ultrarapide pour étudier les dynamiques de plusieurs processus d’interaction laser-matière, notamment l’effet Kerr optique, l’ablation laser et le claquage dans l’air induit par laser. Un système d’imagerie basé sur la technique STAMP (sequentially timed all-optical mapping photography) combinée à une étape de filtrage acousto-optique a été développé et a permis de capturer des phénomènes physiques à l’échelle de la picoseconde ou de la nanoseconde avec un contrôle total des conditions d’illumination, du temps d’exposition et du temps entre les images. Les résultats de cette démonstration de faisabilité sont ainsi multiples et pourraient permettre l’utilisation de techniques d’imagerie ultra-rapide hors d’un environnement de laboratoire.This PhD work is mainly focused on the development of efficient measurement tools for the study of the ultrafast dynamics of various physical phenomena, from those occurring within laser oscillators to laser-matter interactions. The manuscript is separated between interrelated studies dealing with laser physics, ablation dynamics and ultrafast metrology. This work is then partially devoted to the design and implementation of an efficient fiber optical parametric chirped pulse oscillator, where the well-known concept of fiber optical parametric oscillation (FOPO) is combined with the principle of chirped pulse amplification. This led to the efficient generation of high-energy, tunable, synchronized picosecond pulses in specific spectral regions. Simulations of this system has shown great potential in energy scaling and unveiled interesting dynamics. Such dynamics were then investigated using the dispersive Fourier transform technique, which enables the recording of shot-to-shot spectra and provides a large data sets for statistical analysis. This allowed for the energy tracking during the wavelength conversion process and resulted in a better comprehension of its dynamic behaviors. This work was then focused towards the development of a novel ultrafast imaging technique for studying the dynamics of several laser matter interaction processes including the optical Kerr effect, laser ablation and laser-induced air breakdown. An imaging system based on spectrally filtered sequentially timed all-optical mapping photography (SF-STAMP) together with acousto-optics filtering was developed and allowed to capture physical phenomena either in the picosecond or nanosecond time scale with a full control over the illumination conditions, exposure time and time between frames. The outcomes of this feasibility demonstration are manifold and could help to bring such ultrafast techniques out of a laboratory environment

Mesures en temps réel de phénomènes ultra-courts : applications aux oscillateurs laser et à la métrologie optique

This PhD work is mainly focused on the development of efficient measurement tools for the study of the ultrafast dynamics of various physical phenomena, from those occurring within laser oscillators to laser-matter interactions. The manuscript is separated between interrelated studies dealing with laser physics, ablation dynamics and ultrafast metrology. This work is then partially devoted to the design and implementation of an efficient fiber optical parametric chirped pulse oscillator, where the well-known concept of fiber optical parametric oscillation (FOPO) is combined with the principle of chirped pulse amplification. This led to the efficient generation of high-energy, tunable, synchronized picosecond pulses in specific spectral regions. Simulations of this system has shown great potential in energy scaling and unveiled interesting dynamics. Such dynamics were then investigated using the dispersive Fourier transform technique, which enables the recording of shot-to-shot spectra and provides a large data sets for statistical analysis. This allowed for the energy tracking during the wavelength conversion process and resulted in a better comprehension of its dynamic behaviors. This work was then focused towards the development of a novel ultrafast imaging technique for studying the dynamics of several laser matter interaction processes including the optical Kerr effect, laser ablation and laser-induced air breakdown. An imaging system based on spectrally filtered sequentially timed all-optical mapping photography (SF-STAMP) together with acousto-optics filtering was developed and allowed to capture physical phenomena either in the picosecond or nanosecond time scale with a full control over the illumination conditions, exposure time and time between frames. The outcomes of this feasibility demonstration are manifold and could help to bring such ultrafast techniques out of a laboratory environment.Ce travail de doctorat est principalement axé sur le développement d’outils de mesure efficaces dédiés à l’étude des dynamiques ultrarapides de divers phénomènes physiques, des oscillateurs laser jusqu’aux interactions laser-matière. Le manuscrit est ainsi séparé en plusieurs études connexes traitant de la physique des lasers, des dynamiques mises en jeu lors de l’ablation laser et plus généralement de la métrologie ultrarapide. Ce travail est ensuite dans un premier temps consacré à la conception et à la mise en œuvre d’un oscillateur paramétrique fibré à impulsions chirpées innovant, où le concept bien connu d’oscillateur paramétrique à fibre optique (FOPO) est combiné au principe d’amplification à dérive de fréquence. Ce nouveau concept a permis de générer efficacement des impulsions picosecondes synchronisées, accordables et à haute énergie dans des régions spectrales d’intérêt. Les simulations numériques de ce système ont démontré un fort potentiel pour la montée en énergie mais aussi dévoilé des dynamiques intéressantes. Ces dynamiques ont ensuite été étudiées à l’aide de la technique de transformée de Fourier dispersive, qui permet d’enregistrer des spectres tir-à-tir et de fournir efficacement un grand nombre de données pour l’analyse statistique. Cela a permis de suivre les transferts d’énergie pendant les processus de conversion paramétriques et de mieux comprendre leurs dynamiques. Ce travail s’est ensuite orienté vers le développement d’une nouvelle technique d’imagerie ultrarapide pour étudier les dynamiques de plusieurs processus d’interaction laser-matière, notamment l’effet Kerr optique, l’ablation laser et le claquage dans l’air induit par laser. Un système d’imagerie basé sur la technique STAMP (sequentially timed all-optical mapping photography) combinée à une étape de filtrage acousto-optique a été développé et a permis de capturer des phénomènes physiques à l’échelle de la picoseconde ou de la nanoseconde avec un contrôle total des conditions d’illumination, du temps d’exposition et du temps entre les images. Les résultats de cette démonstration de faisabilité sont ainsi multiples et pourraient permettre l’utilisation de techniques d’imagerie ultra-rapide hors d’un environnement de laboratoire