Sidi Mohamed Ben Abdellah University
Recent publications
HIV is a serious disease that threatens and affects capital stock, population composition and economic growth. This research paper aims to study the mathematical modeling and disease dynamics of HIV/AIDS with memory effect. We propose two fractional models in the Caputo sense for HIV/AIDS with and without migration. First, we prove the existence and positivity of both models and calculate the basic reproduction number R 0 using the next generation method. Then, we study the local and global stability of the obtained equilibria. In addition, numerical simulations are provided for different values of the fractional order ρ using the Adams-Bashforth-Moulton fractional scheme, to verify the theoretical results. Moreover, a sensitivity analysis of the parameters for the model with migration is carried out.
Urban areas may affect the richness of avian species. The abundance and diversity of urban landscapes offer breeding habitats and nesting resources for urban-adapted species. In our study, we investigated the breeding birds in urban landscapes of Fez’s historical city (Morocco). We used line-transects to search for nests of breeding species, populations, and habitats counting breeding sites and predicting factors (foraging, nesting resources, and urbanization). Furthermore, four habitats counting green gardens, old city walls, urban farms, and urban forests were prospected to search for nests of breeding birds. Among 13 breeding species including 12 resident-breeders, and one breeding migrant, a total of 109 nests were documented. Five species counting Turdus merula, Sylvia atricapilla, Spilopelia senegalensis, Columba livia, and Coloeus monedula were encountered in green gardens; four species counting Athene noctua, Sturnus unicolor, Passer domesticus, and Tachymarptis melba were observed in old city walls. Falco tinnunculus, Fringilla coelebs, and Accipiter nisus occurred in urban forests; and Streptopelia decaocto in urban farms. The recorded nests were divided between cavities (50 nests) and trees (59 nests). In green spaces, nests were distributed among Olea europaea (17), Citrus aurantium (15), Bambusa vulgaris (11), and Eucalyptus globulus (7). In contrast, Olea oleaster and Cupressus sp. hosted only tree nests each, while Populus sp. and Washingtonia filifera hosted only one nest each. Most nests were recorded in habitats rich in nesting trees and close to water sources. On the contrary, the number of nests decreased as the surface and distance of the habitat to the urban center increased. Our data revealed the diversity, habitat use, and nesting substrates of urban breeding bird communities in Morocco and the Southern slope of the Western Palearctic. Future urban plans must integrate measures to provide suitable breeding resources such as cavities of old walls and a high diversity of urban green spaces for birds to enhance their breeding performances, thus promoting the well-being of the population via increasing biodiversity.
Fried foods and frying oil are subjects that warrant the attention of researchers because of their high consumption. Indeed, frying conditions make these oils very sensitive to lipid oxidation which deteriorates the quality and nutritional properties of the food. In this study, we examined the effect of rosemary extract (ROE), known for its high antioxidant activity, in soybean oil used to fry breaded butterfly shrimp, by measuring the induction period with OXIPRES, total polar material (TPM), peroxide index (PI), and free fatty acids (FFA). This evaluation was performed in comparison with control oils without antioxidants. The results showed a significant difference between the oils according to the analyzed parameters, especially in the final hours of frying. The treatment of the oil with rosemary extract effectively delayed its oxidation, having lower levels in all the oxidation markers that were analyzed. It was also found that rosemary extract is able to reduce oil consumption by fried foods. Therefore, ROE ensures soybean oil a high stability against oxidation and a longer shelf life, making it a good natural alternative to synthetic antioxidants.
The use of electronic devices that incorporate multilayer ceramic capacitors (MLCCs) is on the rise, requiring materials with good electrical properties and a narrow band gap. This study synthesized yttrium-substituted barium titanate (Ba1–xYxTiO3, BYT) using a sol–gel process at 950 °C with varying concentrations of yttrium (0 ≤ x ≤ 0.3). X-ray diffraction analysis showed that the tetragonal phase became less pronounced as the yttrium content increased. The samples had varying grain sizes and porosity, with the BY30%T sample having the narrowest band gap at 2.21 eV. The BYT ceramic with 30% yttrium had a thermal conductivity of up to 7 W/m K and an electrical conductivity down to 0.002 (Ω cm)−1 at 180 °C. The current–voltage characteristics of the BYT MLCC were also studied, showing potential use in next-generation high-capacity MLCCs. This work presents BYT as a promising material for these types of capacitors.
Background: The recent expansion of genomic biobank research in the Arab region in the Middle East North Africa has raised complex ethical and regulatory issues. However, there is a lack of studies regarding the views of Arab researchers involved in such research. We aimed to assess the perceptions and attitudes of Arab researchers regarding these issues in biobank research. Methods: We developed a questionnaire to assess the perceptions and attitudes regarding genetic research of researchers from Egypt, Sudan, Morocco, and Jordan. The questionnaire requested demographic data, perceptions, and attitudes regarding the collection, storage, and use of biospecimens and data, the use of broad consent, data security, data sharing, and community engagement. We used multiple linear regressions to identify predictors of perceptions and attitudes. Results: We recruited 383 researchers. Researchers favored equally the use of broad and tiered consent (44.1% and 39.1%, respectively). Most respondents agreed with the importance of confidentiality protections to ensure data security (91.8%). However, lower percentages were seen regarding the importance of community engagement (64.5%), data sharing with national colleagues and international partners (60.9% and 41.1%, respectively), and biospecimen sharing with national colleagues and international partners (59.9% and 36.2%, respectively). Investigators were evenly split on whether the return of individual research results should depend on the availability or not of a medical intervention that can be offered to address the genetic anomaly (47.5% and 46.4%, respectively). Predictors of attitudes toward biospecimen research included serving on Research Ethics Committees, prior research ethics training, and affiliation with nonacademic institutions. Conclusions: We recommend further exploratory research with researchers regarding the importance of community engagement and to address their concerns about data sharing, with researchers within and outside their countries.
The myoid gonadal stromal tumor is a very rare testicular spindle cell tumor. Few cases have been reported in the literature from 1977 to 2022. It was an emerging entity in the fourth edition of the WHO Classification of Tumors of the Urinary System and Male Genital Organs and has been instated as a full benign entity in the new edition of 2022. We report herein an additional case of a myoid gonadal stromal tumor. It was a 27-year-old man who presented with an asymptomatic mass in his left testicle for 2 months. The mass was confirmed by ultrasound as a 3 cm solid well-circumscribed lesion for which orchiectomy has been performed. The histological analysis of the specimen and the immunohistochemistry staining was consistent with a myoid gonadal stromal tumor. The characteristics of this tumor are summarized in well-circumscribed, nonencapsulated masses of uniform spindle cells, and immunohistochemically, tumor cells coexpress SMA and S-100 protein. The benign behavior of this tumor is demonstrated by our results and those presented in the previous cases reported in the literature.
The current study aims to valorize the roots of a medicinal plant of the family Rabeacea called Rubia tinctorum L. (Rubia t.L.), by phytochemical analyses, and by pointing out the antioxidant and corrosion inhibitory proprieties of the soxhlet extract using different solvent. The content of polyphenols and flavonoids was investigated using colorimetric assays Folin-Ciocalteu, which showed a higher TPC (total phenolic contents) in methanolic extract (129.40 ± 1.78 mg GAE/g), while the flavonoid fraction represents the minor proportion with 63.32 ± 1.41 mg GAE/g. The optimized extract was characterized by UV–vis spectrophotometric analysis and FTIR spectrometric analysis. The antioxidant activities were evaluated using TAC (total antioxidant capacity), DPPH (diphenyl picryl-hydrazyl), free radical scavenging and FRAP method; the obtained results are more significant than those of BHT, ascorbic acid and vitamin E, used as standard. The soxhlet methanolic extract of Rubia tinctorum L. roots was also used as green corrosion inhibitor for low carbon steel (LC-steel) in acid environment (1 M HCl), using the mass loss method and both techniques PDP (potentiodynamic polarization) and EIS (electrochemical impedance spectroscopy) for the electrochemical tests. PDP results reveal that the Rubia t.L. extract functions as a mixed inhibitor. Nyquist plots show that the resistance of charge transfer increases by increasing the inhibitor concentration, whereas the capacity of the double layer decreases. The adsorption of the extract follows the Langmuir isothermal model. The inhibition efficiencies found in the presence of the tested extract through the three electrochemical methods are consistent and are around the value of 95% at the optimum concentration (1 g/l) and a temperature of 298 K.
The acceleration of urbanization leads to a geographical extension of cities, longer distances and travel times, increased motorization, and a constantly growing population. Faced with this situa- tion, new urban policies are attempting to control the interaction between urban planning and urban mobility and to redefine a new dimension of proximity, which reduces excessive use of energy-consuming and polluting modes of travel, namely vehicles. This orientation is embodied in the 15-minute city model, which focuses on pedestrian accessibility from one’s home to nearby services and urban spaces. From this perspective, the paper proposes a GIS-based model to evaluate pedestrian accessibility to mosques. Using the open-source software QGIS, a total number of 30 mosques in the Agdal district in the city of Fez in Morocco were studied to investigate their pedestrian accessibility, by examining their spatial distribution and also their capacity to accom- modate the worshippers of their catchment areas. Considering the land use and the population density of each mosque’s catchment area, the results showed that even if a mosque can be spatially accessible by walking, it may not be able to comfortably satisfy the potential worshippers in its area of influence. Many people are then forced to travel long distances, sometimes by vehicles, to reach other mosques that can eventually accommodate them. The proposed method helps city planners better understand the urban configuration in terms of spatial and functional pedestrian accessibility, for more inclusive and equitable cities.
Seven new molecules (S1-S7) of D-π-D type have been designed for organic photovoltaic applications. The DFT and TD-DFT methods were used to investigate the effect of different central bridge groups on the geometric, optoelectronic, and charge transport properties of the constructed molecules. Among them, S4 and S6 have the lowest energy band gap and a red shift in the absorption spectra, revealing the perfect relationship between the central bridge and the strong electron withdrawal character through extended conjugation. Similarly, S6 explored the lowest reorganization energy (RE) value for electron and hole revealing its enhanced charge transition, also shows better ICT characteristics with its highest NLO properties. Compound S4 showed the smallest value of ∆E(L-L) and Eb, and the highest Voc due to its low HOMO, which improves the photocurrent density of the devices. Thus, the results suggest that bridge modification is a practical strategy to improve the efficiency of OSCs.
In this work, the SnS thin film was deposited on the glass substrate by spray technique at 350 °C. The impact of Cu doping on physical properties of the SnS thin film was investigated using a variable doping concentration [Cu/Sn] from 1 to 5%. XRD revealed that films of polycrystalline nature have orthorhombic crystal structures with a preferential orientation along the (111) plane given that peak intensity decreases with increasing Cu doping concentration. Atomic force microscopy and scanning electron microscopy measurements reveal the dependence of surface roughness and morphology because of copper doping. The optical properties were studied by measuring the transmission characteristics which were used to find the optical band gap energy. The Hall effect measurement results confirm the p type of all samples and that their resistivity is strongly dependent on Cu concentration. The influence of the dopant rate on the PV parameters of simulated SnS-based solar cell was studied using the SCAPS-1D software.
In this work, we made a numerical simulation of heat transfer in a pipe of a flat plate solar collector using two forms of the absorber plate (simple, with baffles) in the presence of obstacles on the insulating plate. The flow is unsteady and laminar where the heat exchange between the absorber and working fluid takes place in useful area. The aim is to study the effects of mass flow and the number of baffles as well as their height on flow and heat transfer characteristics. Several CFD simulations were carried out in order to determine the influencing parameters allowing better performances of the collector and ensuring a good homogeneity of the temperature at the channel outlet. It is shown that when the number and height of baffles increase and the mass flow decreases the mean outlet temperature and the heat transfer rate between fluid and absorber plate are improved.
The COVID -19 pandemic has sparked new perceptions of death—dying has lost its disinterestedness and transpired to be a site of cultural, existential and political struggles, despite efforts to shelve the idea of an unavoidable death from everyday life. Moroccan media, in particular, has centered its focus on mass burials, over-crowded hospitals and spiraling death rates to amplify citizens’ fear of death and thereby coerce them to stay at home in concert with the WHO guidelines. Given their physical and emotional proximity to the virus, this article zooms in on semi-structured narrative interviews with COVID -19 patients from Fez, Morocco, to analyze the implication of their pre-, during- and post-contamination experiences on the novel perceptions of death and dying. It arrives at a pivotal result: the return of symbolic immortality upon recovery when ex-patients become heroes who have succeeded in sidestepping the horror that the media worked untiringly to convey.
Until now, convolutional neural networks (CNNs) still among the powerful and robust deep neural networks that proved its efficiency through several real applications. However, their functioning requires a large number of parameters which in turn lead to some undesired effects such as the overparametrization, overfitting and the high consumption of computational resources. To deal effectively with these issues, we propose in this paper a new multi-objective optimization model for redundancy reduction in CNNs. The suggested model named MoRR-CNN allows to eliminate the unwanted parameters (kernels and weights) as well as to speeding up the CNN evaluation process. It consists of two objectives, the first one is related to the training task where the solution is the optimal parameters. These parameters are combined with a set of decision variables that controlling their contribution in the training process, making at the end a redundancy-related objective function. Both of the objectives are optimized using the non dominated sorting genetic algorithm NSGA-II. The robustness of MoRR-CNN has been demonstrated through different experimentation applied on three benchmark datasets including MNIST, Fashion-MNIST and CIFAR and using three of the most known CNNs such as VGG-19, Net-in-Net and VGG-16.
Herbal medicine was used since the old time in the treatment of different types of diseases in Sefrou province, Morocco. However, few studies have been carried out to identify local medicinal flora and to scientifically document the knowledge of the traditional use of these medicinal plants by the population. This study aims to investigate the medicinal plants in Sefrou province, record their usage in folk medicine by the population and evaluate the hypotensive effect of selected plants using in vitro vascular activity. For that, an ethnobotanical survey was conducted among the Arabs and Amazighs population of Sefrou province from January 2017 to December 2018. The survey was conducted through oral interviews with a structured questionnaire. It covered those who knew and/or used plants for medicinal purposes, retailers, and wholesalers, and also included ecological repartition as well as the mode of administration. Then we selected some plants to evaluate the antihypertensive activity based on the in vitro bioassay. A total of 134 medicinal plants belonging to 52 families were identified; 61% are wild species, 49 (36%) are cultivated and 4 (3%) are cultivated as well as spontaneous. Medicinal plants used in Sefrou folk medicine have been investigated for their antihypertensive activity. They were selected based on their usage as cardiotonic, diuretics, and other uses related to the symptoms of hypertension. Most of the plants tested in this study were found to be more sensitive to relaxing contractions induced by noradrenaline. Out of 32 species examined, 14 (44%) showed more than 50% inhibition in isolated rat aortic rings, the vasorelaxant activity of these plants used for the screening was mostly inhibited by pre-treatment with N-ω-nitro-L-arginine (L-NOArg). The plants inventoried are alleged to be active against 104 therapeutic indications. Nine common symptoms are widely treated in indigenous pharmacopeia: gastrointestinal (19 plants), renal (27 plants), broncho-pulmonary system (7 plants), skin (13 species), diabetes (12 plants), cardiovascular (13 plants), eye, ear, nose, teeth, and throat diseases (5 plants); gynecological disorders (6 plants); rheumatism and gnawing pain (11 plants). 14% (19 species) of the plant inventoried are traded on a large scale and scope and more than 90 percent of the medicinal plants purchased from Sefrou go to big cities for export. The expansion of unregulated trade and commercial use of medicinal and aromatic plants poses a major threat to biodiversity in the region. Overall, people in Sefrou hold rich knowledge of herbal medicine. The vasorelaxant activity proved for the documented plants will provide a basis for other preclinical and clinical investigations. Keywords: medicinal flora; folk-medicine; Sefrou ethnobotany; antihypertensive; pharmacological screening; vasorelaxant activity; medicinal plants' incomes
In this paper, a new control scheme, that combines the Super-Twisting (ST) algorithm with the Nonsingular Terminal Sliding Mode Control (NTSMC), is adopted to robustly stabilize the quadrotor attitude while compensating for the impact of uncertainties/perturbations. The main merit of the proposed ST-NTSMC is to take advantage of the robustness and chattering avoidance allowed by the ST algorithm and the finite-time convergence, the fast transitions, and the high trajectory tracking accuracy allowed by the NTSMC algorithm. Lyapunov criterion is used to analyze the closed-loop stability of the proposed ST-NTSMC controller. Experimental tests are conducted on a quadrotor prototype under various flight conditions in order to test and evaluate the performance of the new controller. Comparisons with multiple linear and nonlinear controllers are also performed to highlight the outperformance of the suggested approach. Experimental results demonstrate the high performance of the developed controller in terms of tracking accuracy, robustness, and chattering reduction.
A simple and versatile preparation of Zn(II)-poly(carboxylates) reticulated binders by the addition of Zn(II) precursors (ZnSO4, ZnO, or Zn(NO3)2) into a preoptimized poly(carboxylic acids) binder solution is proposed. These binders lead systematically to a significantly improved electrochemical performance when used for the formulation of silicon-based negative electrodes. The formation of carboxylate-Zn(II) coordination bonds formation is investigated by rheology and FTIR and NMR spectroscopies. Mechanical characterizations reveal that the coordinated binder offers a better electrode coating cohesion and adhesion to the current collector, as well as higher hardness and elastic modulus, which are even preserved in the presence of a carbonate solvent (i.e., in battery operation conditions). Ultimately, as shown from operando dilatometry experiments, the electrode expansion during lithiation is reduced, mitigating electrode mechanical failure. Such coordinatively reticulated electrodes outperform their uncoordinated counterparts with an improved capacity retention of over 30% after 60 cycles.
This article is concerned with the reliable output tracking control problem for a class of two‐dimensional (2‐D) discrete systems with actuator faults. The systems are described by the well‐known Roesser model. The aim of the problem addressed is to design a reliable controller such that the output of the 2‐D discrete systems tracks the output of a given reference model well in the H∞$$ {H}_{\infty } $$ sense. By resorting to a Lyapunov function and some zero equations, a new criterion on H∞$$ {H}_{\infty } $$ tracking performance analysis is presented. This criterion is then applied to design the tracking controller, for both cases known and unknown actuator failures. Finally, two examples are given to illustrate the effectiveness of the proposed method.
This paper addresses the H∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$_{\infty }$\end{document} filters design problem for delayed nonlinear systems subject to L2−\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}${\mathscr{L}}_{2}-$\end{document}norm disturbances via Takagi-Sugeno (T-S) fuzzy approach with interval time-varying delay. An appropriate Lyapunov-Krasovskii functional (LKF) is established in the framework of augmented system. Then, on the basis of the free-weighting matrix technique and convex method, some improved integral inequality are employed and combined with a decoupling approach without ignoring any useful terms. Therefore, less conservative delay dependent conditions are obtained in terms of linear matrix inequality (LMIs), wish can be solved by using the Matlab LMI toolbox, to achieve the desired H∞\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$_{\infty }$\end{document} performance. Finally, three numerical examples are given to demonstrate the advantages and the effectiveness of the obtained results, compared with some previous method in the literature.
The crystal structure, morphology, and linear and nonlinear optical properties of Co-doped Ba1−xCoxTiO3 (x = 0.00, 0.02, 0.03, 0.04, and 0.06) were investigated using x-ray diffraction (XRD), scanning electron microscopy, and UV–visible spectroscopy measurements. The XRD patterns confirmed that the Ba1−xCoxTiO3 samples crystallized in the perovskite phase, and a transition from quadratic to pseudo-cubic phase was observed with Co doping. Upon doping, the band gap (Eg) decreased from 3.14 eV to 2.11 eV, indicating that Co doping into BaTiO3 caused a change in their electronic levels associated with lattice defects. Additionally, the optical parameters including linear refractive index, extinction coefficient, dielectric coefficient, optical conductivity (σopt), and the static index (n0) were extracted and linked to the Co content. Finally, analysis of the linear (LOp) and nonlinear optical (NLOp) parameters of Ba1−xCoxTiO3 revealed that the increase in Co content induces an increase in the NLOp refractive index (n2) and third-order NLOp susceptibility χ(3).
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5,164 members
Omar Assobhei
  • Department of environment
Abderrazak Hajjioui
  • Physical and Rehabilitation Medicine Department
Said Saddiki
  • Public Law
  • Epidemiology; Public Health
El Achhab Youness
  • Epidemiology, Clinical Research and Community Health Department
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