Étude de la cinétique d’élimination de la matière organique dans un système intégré réacteur anaérobie-chenal algal à haut rendement

Cette étude a pour objectif d’élaborer un modèle empirique basé sur les cinétiques d’élimination de la matière organique dans un système intégré réacteur anaérobie-chenal algal à haut rendement (CAHR), et ce, pour disposer d’un outil de dimensionnement adapté au contexte marocain. Contrairement à l’approche d’Oswald, qui est basée sur le bilan énergétique des algues, ce modèle a été élaboré selon un concept d’ingénierie qui prend en considération les paramètres de conception des réacteurs (débit, charge, etc.).L’originalité de ce modèle consiste en l’introduction d’un paramètre γ qui traduit les phénomènes biologiques au sein du réacteur algal, notamment la symbiose entre les algues et les bactéries. En effet, l’approche de modélisation adoptée est basée sur l’étude de la croissance de la biomasse algo-bactérienne comme étant l’aspect majeur responsable de la dépollution au sein du chenal algal à haut rendement.Cette recherche reflète l’importance de l’inclusion des paramètres biologiques dans la conception d’un bioréacteur algal. À cet effet, nous avons déterminé le facteur γ qui traduit le rapport algues/bactéries en s’appuyant sur le suivi de l’activité algale et la mesure de la matière volatile en suspension au niveau de la station pilote de Rabat. Ce facteur a été évalué par ORON et al. à 1/100. Nous avons confirmé ce chiffre par les résultats expérimentaux.Ainsi, le modèle établi permet, en se fixant un rendement d’élimination dans le chenal algal à haut rendement et connaissant la charge organique entrante au système intégré, de déterminer le temps de séjour dans le chenal et, par la suite, de dimensionner le réacteur. Les limites de validité du modèle ont été vérifiées sur des données expérimentales obtenues dans la station pilote de Rabat et la station d’épuration de la ville d’Ouarzazate.Cette approche de modélisation se trouve vérifiée pour un temps de séjour de un jour et demi à deux jours dans le réacteur anaérobie et pour des charges organiques brutes entrantes au système de l’ordre de 650 mg•L-1.Les essais (deux jours - quatre jours) donnent une meilleure corrélation. Donc, nous pouvons considérer que la combinaison d’un temps de séjour de deux jours dans le réacteur anaérobie et quatre jours dans le chenal algal à haut rendement serait une bonne base de dimensionnement de ces systèmes au Maroc.The objective of this study was to build an empirical model for the design of wastewater plants by using an integrated system comprising an anaerobic reactor and a high rate algal pond. This model is based on the kinetics of elimination of organic matter in the reactors, and, in contrast to the Oswald approach based on the algal energy balance, this model was constructed according to an engineering concept taking into consideration the design parameters of the reactors (flow, charges, etc.). This new approach is characterized by the introduction of a parameter that is indicative of symbiosis between algae and bacteria. In fact, the model is based on the growth of algae-bacteria biomass as a major aspect of depollution in the high efficiency algal channel. The limits of validity of this model have been verified on experimental data collected at the Rabat pilot station located in the Agronomic and Veterinary Hassan II Institute, and from the wastewater treatment plant of the city of Ouarzazate.This work reflects the importance of biological parameters in the conception of an algal bioreactor. The factor γ, which is the algae/bacteria ratio, was evaluated by Oron and collaborators to be around 1/100, a result confirmed using experimental data from the Rabat pilot station. This design approach was verified for a retention time of 1.5 to 2 days in the anaerobic reactor and raw organic loads entering the system around 600 mg•L-1. One can consider that the combination of a retention time of two days in the anaerobic reactor and four days in the High Rate Algal Pond could be a good basis for the design for such systems in Morocco

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

Towards employing mobile phone trading systems to develop and improve the efficiency of the logistics sector in Algeria: نحو توظيف أنظمة التجارة عبر الهاتف المحمول لتطوير وتحسين كفاءة قطاع النقل والإمداد في الجزائر

درست الورقة البحثية إشكالية تطبيق أنظمة التجارة الالكترونية عبر الهاتف المحمول وأثر استخدامها فى تحسين كفاءة قطاع النقل والإمداد في الجزائر، ومعرفة مدى استعداد مؤسسات القطاع لتطبيق هذه الأنظمة، حيث لعبت انظمة التكنولوجيا الرقمية وكذا التطبيقات الذكية دورا هاما في تنويع وتحسين خدمات النقل بمختلف انواعه وطرقه بأكثر جودة واقل التكاليف وفي الوقت المناسب للزبون او المتعامل الاقتصادي ولعل من اهمها تطبيقات تحديد المواقع العالمية ونقاط البيع وكذا انظمة المعلومات الجغرافية. وتهدف الدراسة الى ابراز كيفية توظيف الانظمة والتطبيقات الذكية في تطوير وتحسين جودة خدمات النقل والإمداد لتحديد المواقع والمعلومات الجغرافية وذلك من خلال اعطاء امثلة وتجارب عملية في الجزائر، وقد خلصت الدراسة الى انه مازال فيه عوائق وتحديات تحد من انتشار وزيادة معدل استخدام هذا النوع من التطبيقات والتكنولوجيا في قطاع النقل والامداد بالجزائر الا من خلال تشجيع الابتكار لتكنولوجي وخلق المؤسسات الناشئة البسيطة في هذا القطاع الحيوي.The research paper examined the problem of applying e-commerce systems via mobile phone and the impact of their use in improving the efficiency of the transport and logistics sector in Algeria, and knowing the extent of the sector's willingness to implement these systems, where digital technology systems as well as smart applications have played an important role in diversifying and improving transportation services of various kinds and methods With more quality, less costs, and at the right time for the customer or the economic customer, perhaps the most important one is the applications of global positioning and points of sale, as well as geographical information systems. The study aims to show how smart systems and applications can be used to develop and improve the quality of transport and logistics services to determine locations and geographical information, by giving examples and practical experiences in Algeria. The study concluded that there are still obstacles and challenges that limit the spread and increase in the rate of use of this type of application and technology In the transport and supply sector in Algeria, only by encouraging innovation in technology and creating simple startups in this vital sector

Public services for distribution of drinking water and liquid sanitation in urban zones in Morocco Relevance of introduction the performance indicators for preservation water resources.

Because of the absence of regulations and specific national norms, the unilaterally applied indicators for performance evaluation of water distribution management services are insufficient. This does not pave the way for a clear visibility of water resources. The indicators are also so heterogeneous that they are not in equilibrium with the applied management patterns. In fact: 1- The performance (yield and Linear loss index) of drinking water networks presents a discrepancy between operators and lack of homogeneity in terms of parameters put in its equation. Hence, It these indicators lose efficiency and reliability; 2- Liquid sanitation service has to go beyond the quantitative evaluation target in order to consider the qualitative aspects of water. To reach this aim, a reasonable enlargement of performance indicators is of paramount importance in order to better manage water resource which is becoming scarce and insufficient

Annual Variation in the Performance of Settat Wastewater Stabilization Ponds Located in Settat City, Morocco

The wastewater treatment plant of Settat city uses the natural lagooning technology, which requires low maintenance cost and little technical expertise. The purpose of this study was to evaluate the stability of plant performance during two years of operation (2019 and 2020), as well as the safety of its treated wastewater for reuse in agricultural irrigation. The results of this study show that the biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and suspended solids (SS) did not exceed the Moroccan standards for discharge. They also show a good stable pollutant load reduction with a mean of 86.44%, 86.89% and 74.61%, for BOD5, COD and SS, respectively. On the other hand, microbiological characterization classifies the treated wastewater as "B" quality water, because the fecal coliform numbers exceed the requirement for "A" quality (1000 CFU/100 ml)

Cat swarm optimization for solving the open shop scheduling problem

Abstract This paper aims to prove the efficiency of an adapted computationally intelligence-based behavior of cats called the cat swarm optimization algorithm, that solves the open shop scheduling problem, classified as NP-hard which its importance appears in several industrial and manufacturing applications. The cat swarm optimization algorithm was applied to solve some benchmark instances from the literature. The computational results, and the comparison of the relative percentage deviation of the proposed metaheuristic with other’s existing in the literature, show that the cat swarm optimization algorithm yields good results in reasonable execution time

A homozygous MPZL2 deletion is associated with non syndromic hearing loss in a moroccan family

International audienceAdhesion glycoproteins are implicated in the pathophysiology of hearing loss, the most frequent inherited sensory disorder, affecting 1 in 1000 new-borns. Exome sequencing of a consanguineous Moroccan patient with mild hearing loss identified for the first time in a North African family a single homozygous mutation c.72delA in MPZL2 gene, encoding the Myelin Protein Zero-Like 2, reported as causing deafness in two other populations. Variable tandem repeat genotyping of this family revealed that the c.72delA MPZL2 allele shared a common haplotype with Turkish and Dutch families. These results confirm the pathogenicity of this MPZL2 mutation in recessive mild to moderate non-syndromic deafness

Identification of novel mutations by targeted NGS in Moroccan families clinically diagnosed with a neuromuscular disorder

International audienceBackground and aims: The identification of underlying genes of genetic conditions has expanded greatly in the past decades, which has broadened the field of genes responsible for inherited neuromuscular diseases. We aimed to investigate mutations associated with neuromuscular disorders phenotypes in 2 Moroccan families.Material and methods: Next-generation sequencing combined with Sanger sequencing could assist with under-standing the hereditary variety and underlying disease mechanisms in these disorders. Results: Two novel homozygous mutations were described in this study. The SIL1 mutation is the first identified in the Moroccan population, the mutation was identified as the main cause of Marinesco-Sjogren syndrome in one patient. While the second mutation identified in the fatty acid 2-hydroxylase gene (FA2H) was associated with the Spastic paraplegia 35 in another patient, both transmitted in an autosomal recessive pattern.Discussion and conclusions: These conditions are extremely rare in the North African population and may be underdiagnosed due to overlapping clinical characteristics and heterogeneity of these diseases. We have reported in this study mutations associated with the diseases found in the patients. In addition, we have narrowed the phenotypic spectrum, as well as the diagnostic orientation of patients with neuromuscular disorders, who might have very similar symptoms to other disease groups

Numerical simulation of the quicksand phenomenon by a 3D coupled Discrete Element - Lattice Boltzmann hydromechanical model

International audienceThis paper deals with the numerical simulation of the quicksand phenomenon using a coupled Discrete Elements – Lattice Boltzmann hydromechanical model. After the presentation of the developed numerical model, simulations of ascending fluid flow through granular deposits are performed. The simulations show that the quicksand actually triggers for a hydraulic gradient very close to the critical hydraulic gradient calculated from the global analysis of classical soil mechanics, that is, when the resultant of the applied external pressure balances submerged weight of the deposit. Moreover, they point out that the quicksand phenomenon does not occur only for hydraulic gradients above the critical hydraulic gradient, but also in some cases with slightly lower gradients. In such cases, a more permeable zone is first gradually built at the bottom of the deposit through a grain rearrangement, which increases the hydraulic gradient in the upper zones and triggers the phenomenon