N2 Gas-Flushing Prevents Bacteria-Promoted Lipolysis and Proteolysis and Alleviates Auto-Oxidation in Bovine Raw Milk During Cold-Storage

Peer reviewe

Phospholipolysis Caused by Different Types of Bacterial Phospholipases During Cold Storage of Bovine Raw Milk Is Prevented by N2 Gas Flushing

Cold storage aims to preserve the quality and safety of raw milk from farms to dairies; unfortunately, low temperatures also promote the growth of psychrotrophic bacteria, some of which produce heat-stable enzymes that cause spoilage of milk or dairy products. Previously, N-2 gas flushing of raw milk has demonstrated significant potential as a method to hinder bacterial growth at both laboratory and pilot plant scales. Using a mass spectrometry-based lipidomics approach, we examined the impact of cold storage [at 6 degrees C for up to 7 days, the control condition (C)], on the relative amounts of major phospholipids (phosphatidylethanolamine/PE, phosphatidylcholine/PC, phosphatidylserine/PS, phosphatidylinositol/PI, and sphingomyelin/SM) in three bovine raw milk samples, and compared it to the condition that received additional N-2 gas flushing (N). As expected, bacterial growth was hindered by the N-2-based treatment (over 4 log-units lower at day 7) compared to the non-treated control condition. At the end of the cold storage period, the control condition (C7) revealed higher hydrolysis of PC, SM, PE, and PS (the major species reached 27.2, 26.7, 34.6, and 9.9 mu M, respectively), compared to the N-2-flushed samples (N7) (the major species reached 55.6, 35.9, 54.0, and 18.8 mu M, respectively). C7 samples also exhibited a three-fold higher phosphatidic acid (PA) content (6.8 mu M) and a five-fold higher content (17.3 mu M) of lysophospholipids (LPE, LPC, LPS, and LPI) whereas both lysophospholipids and PA remained at their initial levels for 7 days in N7 samples. Taking into consideration the significant phospholipid losses in the controls, the lipid profiling results together with the microbiological data suggest a major role of phospholipase (PLase) C (PLC) in phospholipolysis during cold storage. However, the experimental data also indicate that bacterial sphingomyelinase C, together with PLases PLD and PLA contributed to the degradation of phospholipids present in raw milk as well, and potential contributions from PLB activity cannot be excluded. Altogether, this lipidomics study highlights the beneficial effects of N-2 flushing treatment on the quality and safety of raw milk through its ability to effectively hinder phospholipolysis during cold storage.Peer reviewe

Using Geochemical and Isotope Investigations for Groundwater Management Strategies Under Semi-Arid Area: Case of the Wadi Ouazzi Basin (Morocco)

The characteristics of Essaouira basin water resources are a semi-arid climate, which is severely impacted by the climate (quantity and quality). Considering the importance of the Essaouira aquifer in the groundwater supply of the region, a study was conducted in order to comprehend this aquifer groundwater evolution. The Essaouira aquifer is a coastal aquifers located on the Atlantic coastline, southern (Morocco), corresponding to a sedimentary basin with an area of near 200 km2.A water sampling from twenty wells, drillings and sources belonging to the Plio-quaternary and Tu-ronian aquifers was realized (what was realized). Samples examined from the ground for electric conductivity and temperature, determined waters belonging to the Plio-quaternary and Turonian aquifers present very variable electric conductivities from 900 µs/cm to 3880 µs/cm. In spite of this variability, they form the same family and are characterized by sodium-chloride facies. There exists, however, a good correlation between the electric conductivity and chloride and sodium contents. Therefore the lower electric conductivities are situated in the North quarter immediately in the south of the Wadi Ouazzi. Keywords: Management, Wadi Ouazzi, Drought, Strategies, Semi-arid, Turonian, Plio-Quaternary

Rôle d'Instagram sur le comportement d’achat des consommateurs marocains en période du COVID-19

With 1 billion monthly active users as of June 2018, Instagram is undoubtedly one of the most popular social networking apps in the world (TechCrunch, 2018). Hashtags have become the lingo of Generation Y. Instagram is a social media networking app that goes far beyond simply uploading and liking photos. This is perhaps one of the crucial reasons for its rise over other social media platforms like Snapchat, Facebook, etc. Indeed, social media platforms, such as Instagram, continue to gain users quickly and increasingly. Brands are using these platforms effectively with new strategies, in order to gain visibility among the public. Among the popular new tactics brands are using is the online "celebrity" known as a social media influencer (SMI). Brands use these celebrities to spread information and influence consumer perceptions. The use of the SMI in communication and marketing campaigns has gained widespread popularity in almost every industry, from beauty and fashion, home and family, health and fitness, travel and lifestyle, food and beverage, business and technology, and entertainment. With the closure of some physical stores, coupled with the potential danger of having to leave home since the first case of Covid19 in Morocco, consumers have turned to online shopping to find the products they need. It is in this perspective that this research takes place. In this article we seek to investigate, "the impact of digital marketing through the influence of social networks on purchasing behavior during a health crisis". For this we will first present the factors that affect the purchasing behavior of Moroccan consumers with reference to Instagram. In the second point, we will discuss the role of Instagram on the purchasing behavior of Moroccan consumers during a health crisis. Finally, we will present the results of the survey we conducted among 200 consumers using Instagram. The results of our research showed that age, income and education level influenced online shopping behavior during the Covid-19 crisis.     JEL Classification: M31 Paper type: Empirical researchAvec 1 milliard d'utilisateurs actifs mensuels en juin 2018, Instagram est sans aucun doute l'une des applications des réseaux sociaux les plus populaires au monde (TechCrunch, 2018). Les hashtags sont devenus le jargon de la génération Y. Instagram constitue une application de réseautage de médias sociaux qui va bien au-delà du simple téléchargement et de l'appréciation de photos. C'est peut-être l'une des raisons cruciales de son essor par rapport aux autres médias sociaux comme Snapchat, Facebook, etc. En effet, les plateformes de médias sociaux, telles qu'Instagram, continuent de gagner rapidement et de plus en plus les utilisateurs. Les marques utilisent ces plateformes de manière efficace avec de nouvelles stratégies, afin de gagner en visibilité auprès du public. Parmi les nouvelles tactiques populaires utilisées par les marques est la « célébrité » en ligne connue sous le nom d'influenceur de médias sociaux (SMI). Les marques utilisent ces célébrités pour diffuser des informations et influencer les perceptions des consommateurs. L'utilisation du SMI dans les campagnes de communication et de marketing a gagné une grande popularité dans presque tous les secteurs, qu'il s'agisse de la beauté et de la mode, de la maison et de la famille, de la santé et de la forme physique, des voyages et du style de vie, de la nourriture et des boissons, des affaires et de la technologie ou du divertissement. Avec la fermeture de certains magasins physiques, couplée au danger potentiel de devoir quitter la maison depuis l'apparition du premier cas de Covid19 au Maroc, les consommateurs se sont tournés vers l’achat en ligne pour trouver les produits dont ils avaient besoin. C’est dans cette perspective que s’inscrit cette recherche. Au niveau de cet article, nous cherchons à nous interroger sur « l’impact du marketing digital à travers l’influence par les réseaux sociaux sur le comportement d’achat en période de crise sanitaire ». Pour cela nous présenterons tout d’abord les facteurs qui affectent le comportement d'achat des consommateurs marocains en référence à Instagram. Au niveau du deuxième point, nous abordons le rôle d’Instagram sur le comportement d’achat des consommateurs marocains en période de crise sanitaire. En dernier lieu nous exposerons les résultats de l’enquête qu’on a menée auprès de 200 consommateurs utilisant Instagram. Les résultats de notre recherche ont montré que l’âge, le revenu et le niveau d’éducation ont exercé une influence sur le comportement d’achat en ligne pendant la crise Covid-19.     Classification JEL : M31 Type de l’article : Recherche appliquée

Design of Controlled Pre-Split Blasting in a Hydroelectric Construction Project

Geologic conditions and design requirements around upstream Nachtigal Falls, in Cameroon, for the hydroelectric construction project on the Sanaga River dictated close control of blasting procedures with very precise geometry to obtain safe and economical excavation lines. Various techniques of pre-split blasting were used in the initial stage of all major excavations. Hole diameters for pre-splitting were 89 mm, and hole spacing ranged from 0.8 to 1m. Explosive charges varied from 1 to 7 kg per hole, and the detonating cord linear charge ranged from 12 to 60g. The contour blasting technique is aimed at controlling overbreak and improving remaining slope stability. Over-break or over-excavation needs to be controlled since its occurrence compromises the operations in terms of safety (instability in the remaining slope; loosening rocks that increase the risk for operational people; an irregular free face for subsequent blasting); and costs (need for reinforcement of the remaining rock structure through costly sustainment systems; increase in concrete volumes in civil works). This paper discusses in detail the design and field implementation of pre-split blasts successfully carried out to achieve clean vertical walls in moderately dipping, though complexly sheared and jointed gneiss. Based on the results of the experiments, we were able to design a pre-splitting pattern both experimentally and in a very cost-effective manner. It is felt that the methods developed on this project could have useful applications on other major construction projects. Doi: 10.28991/CEJ-2023-09-03-05 Full Text: PD

Refrigerated warehouses as intelligent hubs to integrate renewable energy in industrial food refrigeration and to enhance power grid sustainability

Background Independence from fossil fuels, energy diversification, decarbonisation and energy efficiency are key prerequisites to make a national, regional or continental economy competitive in the global marketplace. As Europe is about to generate 20% of its energy demand from Renewable Energy Sources (RES) by 2020, adequate RES integration and renewable energy storage throughout the entire food cold chain must properly be addressed. Scope and approach Refrigerated warehouses for chilled and frozen foods are large energy consumers and account for a significant portion of the global energy demand. Nevertheless, the opportunity for RES integration in the energy supply of large food storage facilities is often neglected. In situ power generation using RES permits capture of a large portion of virtually free energy, thereby reducing dramatically the running costs and carbon footprint, while enhancing the economic competitiveness. In that context, there exist promising engineering solutions to exploit various renewables in the food preservation sector, in combination with the emerging sustainability-enhancing technology of Cryogenic Energy Storage (CES). Key findings and conclusions Substantial research endeavours are driven by the noble objective to turn the Europe's Energy Union into the world's number one in renewable energies. Integrating RES, in synchrony with CES development and proper control, is capable of both strengthening the food refrigeration sector and improving dramatically the power grid balance and energy system sustainability. Hence, this article aims to familiarise stakeholders of the European and global food preservation industry with state-of-the-art knowledge, know-how, opportunities and professional achievements in the concerned field

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

Impact de l'huile de lubrification sur les performances thermodynamiques des pompes à chaleur réversibles

Ce travail concerne l'impact de la présence d'huile sur les performances énergétiques des systèmes frigorifiques. Pour caractériser cet impact, deux propriétés thermodynamiques ont été étudiées: la solubilité et l'enthalpie. Ainsi, une méthode de mesure simple a été présentée, permettant d'étudier le comportement de différents couples frigorigène/huile en phase transitoire ainsi qu'en équilibre stationnaire. Les données expérimentales ont été validées et modélisées. L'utilisation appropriée des courbes de solubilité a démontré le caractère non- azéotropique des couples frigorigène/huile qui se reflète directement sur le calcul d'enthalpie. Pour cette propriété, un modèle thermodynamique a été développé et expérimentalement validé. Son application a conduit à une nouvelle présentation du diagramme de Mollier tenant compte de 1 'huile. L'utilisation de ce diagramme montre, que parmi tous les éléments du circuit, l'évaporateur est plus pénalisé par la présence d'huile. Ses performances sont d'autant plus abaissées que la fraction massique circulante d'huile est élevée, que la surchauffe est faible et que le fluide frigorigène est plus soluble dans 1 'huile. Une étude expérimentale d'une pompe à chaleur réversible a confirmé que si les règles de l'art sont respectées et si le taux de circulation d 'huile dans la machine est inférieur à 2%, l'impact de 1 'huile est réduit. Enfin, une modélisation locale d'une machine frigorifique complète, initialement chargé avec un mélange non-azéotropique, a permis d'analyser le profil de température, du coefficient d'échange et de la composition locale du frigorigène le long du circuit.This work deals with the effect of oil on the energy performances of refrigerating systems. To characterise this impact, two thermodynamic properties were studied: the solubility and the enthalpy. Thus, a simple measurement method was presented, allowing to study both transient and steady-state behaviour of various refrigerant/oil pairs. Thus, experimental data were validated and modelled. The suitable use of the solubility curves showed the zeotropic character of the refrigerant/oil mixture, which is directly reflected on the enthalpy calculation. For this property, a thermodynamic model was developed and experimentally validated. Its application led to a new presentation of the Mollier diagram taking into account the oil presence. It was then shown that, among all the circuit elements, the evaporator is the most penalised by the oil presence. Its performances decrease when the circulating mass fraction of oil increases, the superheat decreases and when the refrigerant-oil solubility increases. An experimental study on a reversible heat pump confirmed that if the circulation mass fraction of oil in the machine is lower than 2%, the impact of oil is reduced. Lastly, a local model of a refrigerating unit, initially charged with a zeotropic mixture, allowed to analyse the profiles of temperature, heat transfer coefficient and local composition of the refrigerant along a circuit.PARIS-CNAM (751032301) / SudocSudocFranceF

Burnout Syndrome in Pediatric Practice

Objectives: Burnout is a common work-related syndrome consisting of emotional exhaustion, depersonalization and diminished feelings of personal accomplishment. Burnout influences the performance and efficiency of the healthcare professionals and therefore the quality of the care provided. This study aims to assess the burnout rates and potential determinants in pediatrics.Methods: A cross-sectional, descriptive study involving physicians practicing pediatrics in the Jeddah area of Saudi Arabia was conducted utilizing the Maslach Burnout Inventory in addition to questions regarding work-related and lifestyle-related factors.Results: One hundred and thirty pediatricians (55% females) were included with age ranging between 25 and 45 years (mean: 30). Most (46%) were consultants and 54% practiced in a university based setting. Burnout scores were abnormal in 107 (82%) and in 45 (34%) the syndrome was severe. Males were more likely to reach a severe burnout category compared to females (40% vs. 31%; p=0.012). Academic pediatricians working in a university setting were much more likely to experience severe burnout compared to their counterparts working in other hospitals (50% vs. 19%; p=0.0005). Consultants were also more likely to experience severe burnout compared to residents and assistants (46% vs. 27%; p=0.03).Conclusion: At least one third of practicing pediatricians suffer from burnout syndrome. Specific strategies should be developed and implemented to limit and prevent professional burnout