Impact of the covid-19 crisis on the moroccan stock market: Modeling the volatility of the m.a.s.i stock market index

The containment measures taken to combat the Covid-19 outbreak caused an economic and financial crisis at the international scale as well as at the national scale. The purpose of this article is to study and analyze the impact of this pandemic crisis on the Moroccan stock market and to show to what extent the containment decisions have negatively impacted the performance of the stock market. We proposed an approach that introduces the Generalized Autoregressive Conditional Heteroscedasticity (GARCH) model to estimate the volatility of the Moroccan All Shares Index (MASI) caused by the uncertainty of the financial situation following the pandemic. The results show that during the study period, the value of the stock market index signaled a significant shock during the period of containment and a high volatility of its profitability, followed by a period of partial recovery after de-containment

Multidisciplinary study of Laurus Nobilis essential oil: From chemical composition to molecular interactions

This study delves into the chemical composition of Laurus Nobilis (LN) essential oil, employing gas chromatography-mass spectrometry (GC-MS) and solid-phase microextraction (HS-SPME). The hydrodistillation process yielded essential oil at 0.5 % on a dry mass basis. Notably, the essential oil is characterized by a predominant presence of eucalyptol and linalool, collectively constituting 64.33 % of the total composition. Additionally, the research sheds light on the antioxidant properties of Laurus Nobilis supported by outcomes from DPPH analysis, b-carotene bleaching, and ABTS+ cation decolorization tests. The DPPH free radical scavenging assay demonstrated an IC50 of 0.86 ± 0.38 mg/ml. The b-carotene/linoleic acid bleach test indicated a IC50 of 2.58 ± 0.10 mg/ml. Comparatively, the ABTS assay revealed antioxidant activity slightly lower than that of ascorbic acid. Molecular docking studies identified caryophyllene, g-elemene, (-)-spathulenol, a-terpineol acetate, and a-terpineol as compounds with the highest anchoring scores on target proteins. These findings underscore the therapeutic significance in modulating target proteins. Keywords: GC-MS; HS-SPME; Molecular docking; Antioxidant activity; Antibacterial activit

Volatility Spillover Effects in the Moroccan Interbank Sector before and during the COVID-19 Crisis

The objective of this paper is to analyze the volatility spillover effects in the Moroccan interbank sector before and during the COVID-19 pandemic crisis using the DY model. Specifically, this study assesses the impact of the recent COVID-19 outbreak on the transmission of volatility among Moroccan banks listed in the Moroccan stock market. The data sample frequency is daily and extends from 1 January 2012 to 31 December 2021, excluding holidays. The empirical results indicate that the volatility spillover index increased during the pandemic crisis. We also found varying degrees of interdependence and spillover effects between the six publicly traded Moroccan banks and the Moroccan banking sector stock index before and during the COVID-19 pandemic crisis

Volatility Spillover Effects of the US, European and Chinese Financial Markets in the Context of the Russia–Ukraine Conflict

The present study aims to investigate the volatility spillover effects in the international financial markets before and during the Russia–Ukraine conflict. The subject of this paper is the study of the influence of the recent war between Russia and Ukraine on the transmission of volatility between the American, European and Chinese stock markets using the DY methodology. The sample period for daily data is from 1 June 2019 to 1 June 2022, excluding holidays. The volatility spillover index increased during the war period, but this increase remains insignificant compared to that recorded during the COVID-19 pandemic crisis. According to the empirical results, we also found varying levels of dependence and spillover effects between the European, American and Chinese stock indices before and during the Russia–Ukraine conflict

Anaerobic Digestion of Agricultural Waste Using Microbial Inocula: Performance and Characterization of Bacterial Communities Using 16S rRNA Sequencing Approach

Anaerobic digestion is considered a beneficial treatment for biogas production (BP). To improve the performance of this bioprocess, the addition of well-selected inocula could be an interesting approach that affects the overall efficiency of the BP. In this study, the reactor performance and energy analysis of liquid-state anaerobic digestion of cattle manure (CM) at high solids concentration (TS%) (94.87%) with six different inocula—two cellulosic (C.I1, C.I2), one lipidic (Li.I), two lactic (La.I1, La.I2), and one saccharidic (Sacc.I)—were investigated. The results showed that inocula improved the biogas production and yield during anaerobic digestion of CM by 109%, 86%, and 52.4%, respectively, when the cellulosic (C.I1), lipidic (Li.I), and lactic (La.I1) inocula were added, compared with the substrate production alone at a substrate/inoculum (S/I) ratio of 5:3 (v/v). The addition of inocula in an appropriate range is useful for the performance of the anaerobic digestion process. In our study, the 16S rRNA sequencing approach was followed to investigate microbial community structure and diversity in the substrate CM and the three inocula that showed a significant improvement in biogas production (C.I1, Li.I, and La.I). The most abundant bacterial populations were found to be Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, with different abundance percentages. Interestingly, C.I1, which resulted in the highest biogas production, showed the dominance of Cyanobacteria (53.44%) belonging mainly to the class Nostocophycidae. This study highlighted the role of inocula in improving biogas production from cattle manure (CM) thanks to their microbial diversity

Structural, dielectric and optical properties of Ta2O5-Bi2O3-P2O5 phosphate glasses

Glass with 5Ta2O5, xBi2O3, (95–x)P2O5 for 10≤ x ≤ 20 mol % formula was obtained by the normal melt-quench technique and identified by DRX, DSC analysis, Infrared spectroscopy, and followed by the study of the dielectric and optical properties. Glass transition temperature (Tg) is found to grow linearlywith bismuth oxide concentration and goes from 524°C for x=10 to 582°C for x=20 mol %. The density ρ increases with increasing Bi2O3 content and molar volume (VM) diminish when Bi2O3 content rises. The IR study shows the presence of BiO6 and PO3 structural groups and reveals depolymerization of the phosphate links by the creation of the Bi–O–P groups which are due to the incorporation of Bi–O bonds. The partial replacement of P2O5 by Bi2O3 shows that the variation of ɛr' and tan δ depend on Bi2O3 contents. By UV absorption, optical properties of glasses were found in the wavelength limit from 250 to 800nm. The energy band gap was calculated using the optical absorption spectrum and was interpreted as a reflection of the structural changes that take place in the glasses as the Bi2O3 content increases