Vehicular Ad-hoc Networks （VANETs） have been suggested as an active and powerful field of research to mitigate environmental problems and challenges. The main challenge in a VANET is to ensure routing with a good Qu...Vehicular Ad-hoc Networks （VANETs） have been suggested as an active and powerful field of research to mitigate environmental problems and challenges. The main challenge in a VANET is to ensure routing with a good Quality of Service （QoS）. The Greedy Perimeter Stateless Routing （GPSR） protocol is one of the most promising position- based routing mechanisms used to overcome this challenge. Its effectiveness depends entirely on the information on a node＇s mobility and the precision of this information. By broadcasting periodic beaconing within trans- mission boundary ranges, GPSR can manage neighbors＇ mobility information and maintain up-to-date lists of neighbours. Nevertheless, information on the position of a neighboring vehicle quickly becomes outdated, which negatively influences the efficiency of the routing. In order to monitor information mobility and to increase the QoS in this challenging area, position estimation needs to he considered. Thus, in this study, we examine the position estimation problem, and propose an improvement to the GPSR protocol, named KF-GPSR, where each vehicle estimates in real time the position of its neighbors using the Kalman filter algorithm. Indeed, by employing this strong estimation technique, it is possible to reduce consid- erably the frequency of exchanged beacon packets, while maintaining high position accuracy. For greater reliability, we also propose an extension to KF-GPSR, called BOD-KF-GPSR, that uses the ＂beacon-on-demand＂ process only if a node needs to rediscover its neighborhood. Simulation experiments using the network simulator NS-2 are presented to demonstrate the ability and usefulness of our two proposals. Here, we compare the pro- posed protocols against diverse common protocols： GPSR, AODV, DSR, and ZRP. The results show that BOD-KF- GPSR achieves a significant enhancement in terms of its packet delivery ratio, routing cost, normalized routing load, end-to-end delay, and throughput.展开更多
Land use and land cover (LULC) represent the ongoing challenge of environmental variation. The understanding of the level and process of its change is the basis for any environmental planning and management. In Morocc...Land use and land cover (LULC) represent the ongoing challenge of environmental variation. The understanding of the level and process of its change is the basis for any environmental planning and management. In Morocco, as everywhere in the world, human population densities are constantly increasing on the coastal zones. This results in a continuous and rapid acceleration of the use of coastal space and an increase in pressures on ecosystems and the different species they contain. The purpose of this study is the analysis of the changes in LULC from 1985 to 2017 in the coastal area of Sebou estuary, situated in the Northwest of the Moroccan Atlantic coast. The changes were identified and assessed after classifying a series of Landsat images taken during 1985, 2002 and 2017. The algorithm used for the classification is the Support Vector Machine (SVM), which yielded results with accuracy higher than 85%. The results of the land use land cover change describe phenomenal urbanization and deforestation, as well as an evolution of the agricultural sector, indicating the impact of anthropization in this vulnerable environment.展开更多
The first-principles density functional calculation is used to investigate the electronic structures and magnetic properties of Mn-doped and N-co-doped ZnO nanofilms.The band structure calculation shows that the band ...The first-principles density functional calculation is used to investigate the electronic structures and magnetic properties of Mn-doped and N-co-doped ZnO nanofilms.The band structure calculation shows that the band gaps of ZnO films with 2,4,and 6 layers are larger than the band gap of the bulk with wurtzite structure and decrease with the increase of film thickness.However,the four-layer ZnO nanofilms exhibit ferromagnetic phases for Mn concentrations less than 24% and 12% for Mn-doping performed in the whole layers and two layers of the film respectively,while they exhibit spin glass phases for higher Mn concentrations.It is also found,on the one hand,that the spin glass phase turns into the ferromagnetic one,with the substitution of nitrogen atoms for oxygen atoms,for nitrogen concentrations higher than 16% and 5% for Mn-doping performed in the whole layers and two layers of the film respectively.On the other hand,the spin-glass state is more stable for ZnO bulk containing 5% of Mn impurities,while the ferromagnetic phase is stable by introducing the p-type carriers into the bulk system.Moreover,it is shown that using the effective field theory for ferromagnetic system,the Curie temperature is close to the room temperature for the undamped Ruderman-Kittel-Kasuya-Yoshida（RKKY） interaction.展开更多
The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maxima...The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maximal velocity. However, the behavior of the satisfaction rate as a function of the coefficient of variance is independent of the maximal velocity. This is in good agreement with empirical results obtained by Lipshtat [Phys. Rev. E 79 066110 （2009）]. Furthermore, our numerical result demonstrates that at low density the satisfaction rate takes higher values, whereas the coefficient of variance is close to zero. The coefficient of variance increases with increasing density, while the satisfaction rate decreases to zero. Moreover, we have also shown that, at low density the coefficient variance depends strongly on the probability of overtaking.展开更多
The aim of the proposed work is to study the solidification process within a rectangular enclosure provided with three internal rectangular fins attached to the left vertical wall of the cavity.This latest is filled w...The aim of the proposed work is to study the solidification process within a rectangular enclosure provided with three internal rectangular fins attached to the left vertical wall of the cavity.This latest is filled with a phase change material(PCM),initially liquid,at a temperature above its melting temperature.The solidification process was initiated by cooling the left wall and fins to a temperature lower than the melting temperature.In order to study and examine the thermal behavior and thermal performance of the proposed system,a mathematical model,based on the conservation equations of mass,momentum and energy was developed.The governing equations and their associated boundary and initial conditions were next adimensionalyzed.Therefore,several controlling parameters were appeared.The volume control method was used to discretize the equations.The resulting algebraic equations were solved iteratively.Numerical investigations were carried out to study and examine the effect of the dimensionless fin length on the hydrodynamic and thermal fields of the flow,the dimensionless heat flux,the solidified mass fraction and the dimensionless time of complete solidification.展开更多
Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functio...Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. Moreover, the studied DMSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.展开更多
The stabilization problem for a class of linear continuous-time systems with time-varying non differentiable delay is solved while imposing positivity in closed-loop. In particular, the synthesis of state-feedback con...The stabilization problem for a class of linear continuous-time systems with time-varying non differentiable delay is solved while imposing positivity in closed-loop. In particular, the synthesis of state-feedback controllers is studied by giving sufficient conditions in terms of linear matrix inequalities(LMIs). The obtained results are then extended to systems with non positive delay matrix by applying a memory controller. The effectiveness of the proposed method is shown by using numerical examples.展开更多
In this work, we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal...In this work, we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal field. The system is formed with NL layers having spins that can take the values σ= ± 1/2 and S =±1,0. The blocking temperature is deduced, for each spin configuration, depending on the crystal field A. The effect of the exchange interaction coupling Jp between the spin configurations σ and S is studied for different values of temperature at fixed crystal field. The established ground-state phase diagram, in the plane （Jp, △）, shows that the only stable configurations are： （1/2,0）, （1/2, ＋1）, and （1/2,- 1）. The thermal magnetization and susceptibility are investigated for the two spin configurations, in the absence as well as in the presence of a crystal field. Finally, we establish the hysteresis cycle for different temperature values, showing that there is almost no remaining magnetization in the absence of the external magnetic field, and that the studied system exhibits a super-paramagnetic behavior.展开更多
Ru and Pd (2 wt%) loaded on pure and on Ndoped carbon nanotubes (NCNTs) were prepared and tested using the isopropyl alcohol decomposition reaction as probe reaction. The presence of nitrogen functionalities (pyridini...Ru and Pd (2 wt%) loaded on pure and on Ndoped carbon nanotubes (NCNTs) were prepared and tested using the isopropyl alcohol decomposition reaction as probe reaction. The presence of nitrogen functionalities (pyridinic, pyrrolic, and quaternary nitrogen) on the nitrogen doped support induced a higher metal dispersion: Pd/NCNT (1.8 nm) < Pd/CNT (4.9 nm), and Ru/NCNT (2.4 nm) < Ru/CNT (3.0 nm). The catalytic activity of the supports was determined first. Isopropyl alcohol conversion produces acetone on CNTs while on NCNTs it led to both dehydration and dehydrogenation products. At 210 °C and in the presence of air, the isopropyl alcohol conversion was higher on the NCNTs (25%) than on the CNTs (11%). The Pd loaded catalysts were more active and more selective than the Ru ones. At 115 °C, the Pd catalysts were 100% selective towards acetone for a conversion of 100%, whereas the Ru catalysts led to dehydration and dehydrogenation products. The nitrogen doping induced the appearance of redox properties when oxygen is present in the reaction mixture.展开更多
Biodiesel was produced at small scale by transesterification of used frying oil（UFO） recovered from Moroccan pastry shops and fish frying restaurants. Biodiesel was first synthesised at laboratory scale in order to ...Biodiesel was produced at small scale by transesterification of used frying oil（UFO） recovered from Moroccan pastry shops and fish frying restaurants. Biodiesel was first synthesised at laboratory scale in order to optimize the transesterification parameters. The cost of the final product was also optimized using low-cost raw materials.The UFO and the produced biodiesel were characterized with several techniques including gas chromatography,1H NMR,13 C NMR, FTIR, and TGA–TDA techniques.1H NMR gas chromatographic analyses of the final product confirmed that the transesterification in the chosen experimental conditions was completed. These results were confirmed by TGA–TDA analysis used as new techniques to monitoring triglyceride conversion. The biodiesel did not contain any trace of glycerol, and it did meet the international standards. The transesterification at low cost in small scale conditions was performed at 60 ℃ using 1.2% of KOH and a methanol/oil molar ratio of 6：1. A yield of 80.8% was achieved. The properties of the produced biodiesel were found to be as good as those of biodiesels obeying to European standards. The biodiesel production was also performed at small-scale for individual utilisation. Thus, the product was tested in a kerosene stove for heating and non-modified commercial diesel engine producing electricity.展开更多
This study evaluates the annual loss of soil in the sub-basin of Oued Haricha (Tahaddart basin, Western Rif, NW Morocco). The integration of revised (RUSLE) and modified (MUSLE) soil loss empirical equations of Wischm...This study evaluates the annual loss of soil in the sub-basin of Oued Haricha (Tahaddart basin, Western Rif, NW Morocco). The integration of revised (RUSLE) and modified (MUSLE) soil loss empirical equations of Wischmeier and Smith in combination with GIS permits the modelling of soil erosion at the scale of parcels. The characteristics of precipitation and runoff, the soil properties, the culture system and the current working practices of soil in the sub-basin of the Oued Haricha are collected from local data. The digital terrain model is used to generate topographic factors. The combination of different RUSLE factors shows that the annual soil is 62.72 t/ha/year and corresponds to an average level of risk. The total losses calculated by MUSLE method are valued at 221,468 t/year. The rates of loss due to linear erosion are 82,652 t/year. These soil losses represent 20.33% of the total losses, and confirm that the losses on the slopes outweigh the losses due to the river system. Sedimentation module shows that the areas of high erosion (greater than 200 t/ha/year) are concentrated in the reliefs with average and high slope and occupy 38% of the total area. The deposition areas occupy the centre of sub-basin and constitute 9.12% of the total area. These deposits were concentrated on the edges of major rivers and the outlet of the sub-basin and contributed to siltation of the April 9, 1947 dam.展开更多
The aim of this study was to test the impact of Rhizophagus irregularis, an arbuscular mycorrhizal fungus (AMF), on durum wheat growth and soil microbial functionalities in a field inoculation trial conducted in Moroc...The aim of this study was to test the impact of Rhizophagus irregularis, an arbuscular mycorrhizal fungus (AMF), on durum wheat growth and soil microbial functionalities in a field inoculation trial conducted in Morocco. The results showed that i) the R. irregularis inoculum effectively improved wheat growth, ii) wheat growth promotion depended on the soil mycorrhizal infectivity and iii) functional abilities of soil microflora depended on AMF inoculation. This study confirms that field AMF inoculation can be proposed as an effective agronomic practice in wheat production and as a sustainable cultural practice to manage soil biofunctioning. To fully promote inoculation practices, a better knowledge of AMF ecology has to be acquired to better adapt AMF inoculation to environmental conditions, and thus warrant better yields and agricultural sustainability.展开更多
Background: Pregnancy is typically accompanied by an increase of micronutrient requirements in general and especially iron. This increased need may be an additional risk factor for developing anemia. Purpose of the st...Background: Pregnancy is typically accompanied by an increase of micronutrient requirements in general and especially iron. This increased need may be an additional risk factor for developing anemia. Purpose of the study: The aim of this study is to provide data on the prevalence of anemia of pregnancy in the maternity ward of the regional hospital in the city of Temara, and examine risk factors that may expose women to anemia during pregnancy. Materiel and Methods: A prospective cross-sectional study of a year was conducted to the hospital Sidi Lahcen in the city of Temara. Sociodemographic and nutritional data were collected through a questionnaire, obstetric and medical histories of women in labor and the results of biological tests were recorded from the patient obstetric file. Results: Among the 849 women surveyed, 690 (82%) had performed a blood count, and among these 117 (16.8%) were found anemic, with the following proportions: 57.6% had mild anemia, 41.5% had moderate anemia and a minority (0.8%) had severe anemia. The pregnant women aged over 35 years were the most exposed to anemia during pregnancy (47%) compared with younger women (p < 0.001). Women who had a history of anemia aside from pregnancy and those who had anemia in earlier pregnancies were more prone to developing anemia in the current pregnancy with a statistically significant difference (p < 0.001). The number of pregnancies, number of previous abortions and place of residence had no influence on the occurrence of anemia of pregnancy. The consumption of fortified flour with iron and vitamins as well as consuming iron rich foods was not a protective factor against the development of anemia of pregnancy. Tea consumption near the meal was not a factor exposing to anemia during pregnancy. Conclusion: Anemia is a public health problem in Morocco. Evidence from our study emphasizes the need to implement educational programs to improve the nutritional knowledge and sensitization of women.展开更多
Objective: To assess knowledge and behaviour related to toxoplasmosis which remains a neglected disease in Morocco.Methods: Observational investigations were conducted among 600 pregnant women from Essaouira Province....Objective: To assess knowledge and behaviour related to toxoplasmosis which remains a neglected disease in Morocco.Methods: Observational investigations were conducted among 600 pregnant women from Essaouira Province.The interview items covered respondents' knowledge of the disease, its preventive practices and risk behaviours.Results: A total of 22/600 women had already carried out the anti-toxoplasmosis test, while, 96% have never done any screening of anti-Toxoplasma antibodies.Only 16/600 women have good information about the disease, its mode of transmission and its complications in both the fetus and his mother.Although most women adopt a healthy diet, the consumption of raw or undercooked meat is far to be considered as a risk factor, along with other potential factors that may foster the acquisition of the disease, such as possessing a domestic cat, educational status and knowledge of the disease.However, in this study, contact with soil was revealed the most important risk factor(P = 0.045), followed by the hygiene conditions after handling raw meat(P = 0.048).Conclusion: The underestimation of the Toxoplasma gondii sero-prevalence in Essaouira Province can be explained by the absence of toxoplasmosis serology in health institutions, as well as the gap of knowledge about the disease by local population.展开更多
By using first-principles calculations we studied the electronic, optical and magnetic properties of ZnO co-doped with Eu and Pm. In this calculation, we used Wien2 k code based on full potential linearized augmented ...By using first-principles calculations we studied the electronic, optical and magnetic properties of ZnO co-doped with Eu and Pm. In this calculation, we used Wien2 k code based on full potential linearized augmented plane waves(FP-LAPW) method with the modified Becke-Johnson(mBJ) approximation. This correction gives good band gap compared to experimental band gap. The introduction of Eu and Pm codoping leads to an increase in the band gap. Electrons can transit easily from the valence band to the conduction band, which results in an enhancement of visible light absorption in a wider absorption range. Absorption spectra reach a high value in visible and infrared light regions. With the significance of the obtained results, the studied compounds may potentially find spintronic and optoelectronic applications.展开更多
Atlantic forest natural soil flora was tested on two leguminous pioneer species Acacia gummifera and Retama monosperma to be used in rehabilitation programs of the coastal sand dunes forest of the Essaouira region.The...Atlantic forest natural soil flora was tested on two leguminous pioneer species Acacia gummifera and Retama monosperma to be used in rehabilitation programs of the coastal sand dunes forest of the Essaouira region.The rhizospheric soil of two endemic plant species:R.nonosperma and Juniperus phoenicea was sampled and split into two categories,one from native rhizospheric soil,the other of the sterilized rhizospheric soil.Investigation was focused on mycorrhizal formations,but other forms of beneficial symbiosis such as rhizobia and viable soil microflora were also studied.Growth and nutrition variables assessed included lengths of roots and shoots,number of branches,ratio of root to shoot dry mass and water,nitrogen and phosphorus levels.Results showed important mycorrhizal associations in roots of both plants,presence of nodules and abundance of viable soil microflora.J.phoenicea had a 100%frequency of mycorrhizal formation and an intensity of 80%compared to a frequency of 80%and intensity of 54%for R.monosperma.Nodules had the same density of CFU regardless of the origin.Abundance of viable microflora in rhisospheric soil of R.monosperma,J.phoenicea and the control differed significantly.Among the studied variables for A.gummifera and R.monosperma,nitrogen and phosphorus uptakes significantly wit the use of the nonsterilized rhizospheric soil.Both species doubled their phosphorus uptake when colonized by mycorrhizal species,R.monosperma doubled its nitrogen uptake and A.gummifera increased it by seven times compared with the control.No significant difference was noted for the other variables.展开更多
The dynamics of the maximum entangled coherent state traveling through an amplitude damping channel is investigated. For small values of the transmissivity rate, the traveling state is very fragile to this noise chann...The dynamics of the maximum entangled coherent state traveling through an amplitude damping channel is investigated. For small values of the transmissivity rate, the traveling state is very fragile to this noise channel, which suffers from the phase flip error with high probability. The entanglement decays smoothly for larger values of the transmissivity rate and speedily for smaller values of this rate. As the number of modes increases, the traveling state over this noise channel quickly loses its entanglement. The odd and even states vanish at the same value of field intensity.展开更多
The Bactrocera oleae Rossi fly is the most important olive pest. It is of major economic importance in the olive production area of Essaouira, where weather conditions are optimal for the conduct of the various stages...The Bactrocera oleae Rossi fly is the most important olive pest. It is of major economic importance in the olive production area of Essaouira, where weather conditions are optimal for the conduct of the various stages of its life cycle. The lack of phytosanitary treatments worsens this situation. The development of the larval stages and different generations are related to the phenological stages of the olive and are controlled by changes in habitat conditions. Trapping of adult males by Deltas traps baited with sex pheromone, at the four study sites, has identified some characteristics of the evolution of the adult populations’ flight dynamics. Our main results show a decreasing gradient of early emergences of different stages from the coast to the continental areas as well as the absence of the summer generation at the inner station. Soil analysis in the two stations showed that the hypogenous pupae wintering in the soil survive until June. Knowledge of the factors involved in the bio-ecology of the olive fly and the phenology of the host allows the elaboration of monitoring/ warning calendars, and phytosanitary measures in order to establish an IPM program adapted to the requirements of olive orchards in the region.展开更多
Worldwide, large studies have shown that the menopause is mainly associated with substantial changes in body composition that result in an increase in waist circumference, fat accumulation and specially weight gain. T...Worldwide, large studies have shown that the menopause is mainly associated with substantial changes in body composition that result in an increase in waist circumference, fat accumulation and specially weight gain. This overweight could be exacerbated by fat intake. Thus, this study was planned to evaluate the impact of the consumption of olive and argane oils on anthropometric profile and body composition of postmenopausal women. The nutritional intervention was conducted over a period of eight weeks, involving daily consumption of 25 mL of argane oil The anthropometric profile （weight, height and body mass index or olive oil in 151 postmenopausal women （55.49 ± 6.18 years old）. （BMI）） and body composition （fat mass （FM） and lean mass （LM）） were determined at 0 week （baseline）, and after the 4th and 8th weeks of nutritional intervention. Results clearly demonstrated that argane oil or olive oil consumption did not affect the anthropometric parameters and the body composition of postmenopausal women. Thus, argane and/or olive oils＇ regular diet does not lead to weight gain, and postmenopausal women could benefit from their impact on health for a better quality of life and to overcome all menopause associated problems. A longer period of nutritional intervention is required to confirm the trend down that was recorded.展开更多
In organic lettuce cultivation,snails can cause great economic loss.There is a lack of effective control methods for these molluscs.This work is focused on the development of a new agricultural plastic mulch material ...In organic lettuce cultivation,snails can cause great economic loss.There is a lack of effective control methods for these molluscs.This work is focused on the development of a new agricultural plastic mulch material based on low density polyethylene(LDPE),as it is the most widely used polymer in plasticulture.The objective was to develop a new bio-based plastic mulch material that is insect repellent and anti-biofilm by incorporating a bioactive substance into the conventional formulation of the material.A new plastic mulching film made of 0.1%cade oil as was produced using the extrusion process.Bioadhesion tests carried out with aqueous suspensions of Escherichia coli and Pseudomonas aeruginosa show that this material is endowed with anti-biofilm effects.This study will demonstrate how to act by repulsive effect to Helix aspersa against this devastating mollusk in salads culture.展开更多
文摘Vehicular Ad-hoc Networks （VANETs） have been suggested as an active and powerful field of research to mitigate environmental problems and challenges. The main challenge in a VANET is to ensure routing with a good Quality of Service （QoS）. The Greedy Perimeter Stateless Routing （GPSR） protocol is one of the most promising position- based routing mechanisms used to overcome this challenge. Its effectiveness depends entirely on the information on a node＇s mobility and the precision of this information. By broadcasting periodic beaconing within trans- mission boundary ranges, GPSR can manage neighbors＇ mobility information and maintain up-to-date lists of neighbours. Nevertheless, information on the position of a neighboring vehicle quickly becomes outdated, which negatively influences the efficiency of the routing. In order to monitor information mobility and to increase the QoS in this challenging area, position estimation needs to he considered. Thus, in this study, we examine the position estimation problem, and propose an improvement to the GPSR protocol, named KF-GPSR, where each vehicle estimates in real time the position of its neighbors using the Kalman filter algorithm. Indeed, by employing this strong estimation technique, it is possible to reduce consid- erably the frequency of exchanged beacon packets, while maintaining high position accuracy. For greater reliability, we also propose an extension to KF-GPSR, called BOD-KF-GPSR, that uses the ＂beacon-on-demand＂ process only if a node needs to rediscover its neighborhood. Simulation experiments using the network simulator NS-2 are presented to demonstrate the ability and usefulness of our two proposals. Here, we compare the pro- posed protocols against diverse common protocols： GPSR, AODV, DSR, and ZRP. The results show that BOD-KF- GPSR achieves a significant enhancement in terms of its packet delivery ratio, routing cost, normalized routing load, end-to-end delay, and throughput.
文摘Land use and land cover (LULC) represent the ongoing challenge of environmental variation. The understanding of the level and process of its change is the basis for any environmental planning and management. In Morocco, as everywhere in the world, human population densities are constantly increasing on the coastal zones. This results in a continuous and rapid acceleration of the use of coastal space and an increase in pressures on ecosystems and the different species they contain. The purpose of this study is the analysis of the changes in LULC from 1985 to 2017 in the coastal area of Sebou estuary, situated in the Northwest of the Moroccan Atlantic coast. The changes were identified and assessed after classifying a series of Landsat images taken during 1985, 2002 and 2017. The algorithm used for the classification is the Support Vector Machine (SVM), which yielded results with accuracy higher than 85%. The results of the land use land cover change describe phenomenal urbanization and deforestation, as well as an evolution of the agricultural sector, indicating the impact of anthropization in this vulnerable environment.
文摘The first-principles density functional calculation is used to investigate the electronic structures and magnetic properties of Mn-doped and N-co-doped ZnO nanofilms.The band structure calculation shows that the band gaps of ZnO films with 2,4,and 6 layers are larger than the band gap of the bulk with wurtzite structure and decrease with the increase of film thickness.However,the four-layer ZnO nanofilms exhibit ferromagnetic phases for Mn concentrations less than 24% and 12% for Mn-doping performed in the whole layers and two layers of the film respectively,while they exhibit spin glass phases for higher Mn concentrations.It is also found,on the one hand,that the spin glass phase turns into the ferromagnetic one,with the substitution of nitrogen atoms for oxygen atoms,for nitrogen concentrations higher than 16% and 5% for Mn-doping performed in the whole layers and two layers of the film respectively.On the other hand,the spin-glass state is more stable for ZnO bulk containing 5% of Mn impurities,while the ferromagnetic phase is stable by introducing the p-type carriers into the bulk system.Moreover,it is shown that using the effective field theory for ferromagnetic system,the Curie temperature is close to the room temperature for the undamped Ruderman-Kittel-Kasuya-Yoshida（RKKY） interaction.
文摘The satisfaction rate of desired velocity in the case of a mixture of fast and slow vehicles is studied by using a cellular automaton method. It is found that at low density the satisfaction rate depends on the maximal velocity. However, the behavior of the satisfaction rate as a function of the coefficient of variance is independent of the maximal velocity. This is in good agreement with empirical results obtained by Lipshtat [Phys. Rev. E 79 066110 （2009）]. Furthermore, our numerical result demonstrates that at low density the satisfaction rate takes higher values, whereas the coefficient of variance is close to zero. The coefficient of variance increases with increasing density, while the satisfaction rate decreases to zero. Moreover, we have also shown that, at low density the coefficient variance depends strongly on the probability of overtaking.
文摘The aim of the proposed work is to study the solidification process within a rectangular enclosure provided with three internal rectangular fins attached to the left vertical wall of the cavity.This latest is filled with a phase change material(PCM),initially liquid,at a temperature above its melting temperature.The solidification process was initiated by cooling the left wall and fins to a temperature lower than the melting temperature.In order to study and examine the thermal behavior and thermal performance of the proposed system,a mathematical model,based on the conservation equations of mass,momentum and energy was developed.The governing equations and their associated boundary and initial conditions were next adimensionalyzed.Therefore,several controlling parameters were appeared.The volume control method was used to discretize the equations.The resulting algebraic equations were solved iteratively.Numerical investigations were carried out to study and examine the effect of the dimensionless fin length on the hydrodynamic and thermal fields of the flow,the dimensionless heat flux,the solidified mass fraction and the dimensionless time of complete solidification.
文摘Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. Moreover, the studied DMSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.
文摘The stabilization problem for a class of linear continuous-time systems with time-varying non differentiable delay is solved while imposing positivity in closed-loop. In particular, the synthesis of state-feedback controllers is studied by giving sufficient conditions in terms of linear matrix inequalities(LMIs). The obtained results are then extended to systems with non positive delay matrix by applying a memory controller. The effectiveness of the proposed method is shown by using numerical examples.
文摘In this work, we use Monte Carlo simulations to study the magnetic properties of a nanowire system based on a honeycomb lattice, in the absence as well as in the presence of both an external magnetic field and crystal field. The system is formed with NL layers having spins that can take the values σ= ± 1/2 and S =±1,0. The blocking temperature is deduced, for each spin configuration, depending on the crystal field A. The effect of the exchange interaction coupling Jp between the spin configurations σ and S is studied for different values of temperature at fixed crystal field. The established ground-state phase diagram, in the plane （Jp, △）, shows that the only stable configurations are： （1/2,0）, （1/2, ＋1）, and （1/2,- 1）. The thermal magnetization and susceptibility are investigated for the two spin configurations, in the absence as well as in the presence of a crystal field. Finally, we establish the hysteresis cycle for different temperature values, showing that there is almost no remaining magnetization in the absence of the external magnetic field, and that the studied system exhibits a super-paramagnetic behavior.
文摘Ru and Pd (2 wt%) loaded on pure and on Ndoped carbon nanotubes (NCNTs) were prepared and tested using the isopropyl alcohol decomposition reaction as probe reaction. The presence of nitrogen functionalities (pyridinic, pyrrolic, and quaternary nitrogen) on the nitrogen doped support induced a higher metal dispersion: Pd/NCNT (1.8 nm) < Pd/CNT (4.9 nm), and Ru/NCNT (2.4 nm) < Ru/CNT (3.0 nm). The catalytic activity of the supports was determined first. Isopropyl alcohol conversion produces acetone on CNTs while on NCNTs it led to both dehydration and dehydrogenation products. At 210 °C and in the presence of air, the isopropyl alcohol conversion was higher on the NCNTs (25%) than on the CNTs (11%). The Pd loaded catalysts were more active and more selective than the Ru ones. At 115 °C, the Pd catalysts were 100% selective towards acetone for a conversion of 100%, whereas the Ru catalysts led to dehydration and dehydrogenation products. The nitrogen doping induced the appearance of redox properties when oxygen is present in the reaction mixture.
基金Hassan II Academy of Science and Technology for the financial support kindly provided to this researchThe bilateral project CNRST–CNR(2014–2015)
文摘Biodiesel was produced at small scale by transesterification of used frying oil（UFO） recovered from Moroccan pastry shops and fish frying restaurants. Biodiesel was first synthesised at laboratory scale in order to optimize the transesterification parameters. The cost of the final product was also optimized using low-cost raw materials.The UFO and the produced biodiesel were characterized with several techniques including gas chromatography,1H NMR,13 C NMR, FTIR, and TGA–TDA techniques.1H NMR gas chromatographic analyses of the final product confirmed that the transesterification in the chosen experimental conditions was completed. These results were confirmed by TGA–TDA analysis used as new techniques to monitoring triglyceride conversion. The biodiesel did not contain any trace of glycerol, and it did meet the international standards. The transesterification at low cost in small scale conditions was performed at 60 ℃ using 1.2% of KOH and a methanol/oil molar ratio of 6：1. A yield of 80.8% was achieved. The properties of the produced biodiesel were found to be as good as those of biodiesels obeying to European standards. The biodiesel production was also performed at small-scale for individual utilisation. Thus, the product was tested in a kerosene stove for heating and non-modified commercial diesel engine producing electricity.
文摘This study evaluates the annual loss of soil in the sub-basin of Oued Haricha (Tahaddart basin, Western Rif, NW Morocco). The integration of revised (RUSLE) and modified (MUSLE) soil loss empirical equations of Wischmeier and Smith in combination with GIS permits the modelling of soil erosion at the scale of parcels. The characteristics of precipitation and runoff, the soil properties, the culture system and the current working practices of soil in the sub-basin of the Oued Haricha are collected from local data. The digital terrain model is used to generate topographic factors. The combination of different RUSLE factors shows that the annual soil is 62.72 t/ha/year and corresponds to an average level of risk. The total losses calculated by MUSLE method are valued at 221,468 t/year. The rates of loss due to linear erosion are 82,652 t/year. These soil losses represent 20.33% of the total losses, and confirm that the losses on the slopes outweigh the losses due to the river system. Sedimentation module shows that the areas of high erosion (greater than 200 t/ha/year) are concentrated in the reliefs with average and high slope and occupy 38% of the total area. The deposition areas occupy the centre of sub-basin and constitute 9.12% of the total area. These deposits were concentrated on the edges of major rivers and the outlet of the sub-basin and contributed to siltation of the April 9, 1947 dam.
文摘The aim of this study was to test the impact of Rhizophagus irregularis, an arbuscular mycorrhizal fungus (AMF), on durum wheat growth and soil microbial functionalities in a field inoculation trial conducted in Morocco. The results showed that i) the R. irregularis inoculum effectively improved wheat growth, ii) wheat growth promotion depended on the soil mycorrhizal infectivity and iii) functional abilities of soil microflora depended on AMF inoculation. This study confirms that field AMF inoculation can be proposed as an effective agronomic practice in wheat production and as a sustainable cultural practice to manage soil biofunctioning. To fully promote inoculation practices, a better knowledge of AMF ecology has to be acquired to better adapt AMF inoculation to environmental conditions, and thus warrant better yields and agricultural sustainability.
文摘Background: Pregnancy is typically accompanied by an increase of micronutrient requirements in general and especially iron. This increased need may be an additional risk factor for developing anemia. Purpose of the study: The aim of this study is to provide data on the prevalence of anemia of pregnancy in the maternity ward of the regional hospital in the city of Temara, and examine risk factors that may expose women to anemia during pregnancy. Materiel and Methods: A prospective cross-sectional study of a year was conducted to the hospital Sidi Lahcen in the city of Temara. Sociodemographic and nutritional data were collected through a questionnaire, obstetric and medical histories of women in labor and the results of biological tests were recorded from the patient obstetric file. Results: Among the 849 women surveyed, 690 (82%) had performed a blood count, and among these 117 (16.8%) were found anemic, with the following proportions: 57.6% had mild anemia, 41.5% had moderate anemia and a minority (0.8%) had severe anemia. The pregnant women aged over 35 years were the most exposed to anemia during pregnancy (47%) compared with younger women (p < 0.001). Women who had a history of anemia aside from pregnancy and those who had anemia in earlier pregnancies were more prone to developing anemia in the current pregnancy with a statistically significant difference (p < 0.001). The number of pregnancies, number of previous abortions and place of residence had no influence on the occurrence of anemia of pregnancy. The consumption of fortified flour with iron and vitamins as well as consuming iron rich foods was not a protective factor against the development of anemia of pregnancy. Tea consumption near the meal was not a factor exposing to anemia during pregnancy. Conclusion: Anemia is a public health problem in Morocco. Evidence from our study emphasizes the need to implement educational programs to improve the nutritional knowledge and sensitization of women.
文摘Objective: To assess knowledge and behaviour related to toxoplasmosis which remains a neglected disease in Morocco.Methods: Observational investigations were conducted among 600 pregnant women from Essaouira Province.The interview items covered respondents' knowledge of the disease, its preventive practices and risk behaviours.Results: A total of 22/600 women had already carried out the anti-toxoplasmosis test, while, 96% have never done any screening of anti-Toxoplasma antibodies.Only 16/600 women have good information about the disease, its mode of transmission and its complications in both the fetus and his mother.Although most women adopt a healthy diet, the consumption of raw or undercooked meat is far to be considered as a risk factor, along with other potential factors that may foster the acquisition of the disease, such as possessing a domestic cat, educational status and knowledge of the disease.However, in this study, contact with soil was revealed the most important risk factor(P = 0.045), followed by the hygiene conditions after handling raw meat(P = 0.048).Conclusion: The underestimation of the Toxoplasma gondii sero-prevalence in Essaouira Province can be explained by the absence of toxoplasmosis serology in health institutions, as well as the gap of knowledge about the disease by local population.
文摘By using first-principles calculations we studied the electronic, optical and magnetic properties of ZnO co-doped with Eu and Pm. In this calculation, we used Wien2 k code based on full potential linearized augmented plane waves(FP-LAPW) method with the modified Becke-Johnson(mBJ) approximation. This correction gives good band gap compared to experimental band gap. The introduction of Eu and Pm codoping leads to an increase in the band gap. Electrons can transit easily from the valence band to the conduction band, which results in an enhancement of visible light absorption in a wider absorption range. Absorption spectra reach a high value in visible and infrared light regions. With the significance of the obtained results, the studied compounds may potentially find spintronic and optoelectronic applications.
基金This work was supported by the Cadi Ayyad University and"Laboratoire Ecologie et Environnement(L2E)"an associated unit to the "Centre National de la Recherche Scientifique et Technologique(CNRST)"URAC32.
文摘Atlantic forest natural soil flora was tested on two leguminous pioneer species Acacia gummifera and Retama monosperma to be used in rehabilitation programs of the coastal sand dunes forest of the Essaouira region.The rhizospheric soil of two endemic plant species:R.nonosperma and Juniperus phoenicea was sampled and split into two categories,one from native rhizospheric soil,the other of the sterilized rhizospheric soil.Investigation was focused on mycorrhizal formations,but other forms of beneficial symbiosis such as rhizobia and viable soil microflora were also studied.Growth and nutrition variables assessed included lengths of roots and shoots,number of branches,ratio of root to shoot dry mass and water,nitrogen and phosphorus levels.Results showed important mycorrhizal associations in roots of both plants,presence of nodules and abundance of viable soil microflora.J.phoenicea had a 100%frequency of mycorrhizal formation and an intensity of 80%compared to a frequency of 80%and intensity of 54%for R.monosperma.Nodules had the same density of CFU regardless of the origin.Abundance of viable microflora in rhisospheric soil of R.monosperma,J.phoenicea and the control differed significantly.Among the studied variables for A.gummifera and R.monosperma,nitrogen and phosphorus uptakes significantly wit the use of the nonsterilized rhizospheric soil.Both species doubled their phosphorus uptake when colonized by mycorrhizal species,R.monosperma doubled its nitrogen uptake and A.gummifera increased it by seven times compared with the control.No significant difference was noted for the other variables.
文摘The dynamics of the maximum entangled coherent state traveling through an amplitude damping channel is investigated. For small values of the transmissivity rate, the traveling state is very fragile to this noise channel, which suffers from the phase flip error with high probability. The entanglement decays smoothly for larger values of the transmissivity rate and speedily for smaller values of this rate. As the number of modes increases, the traveling state over this noise channel quickly loses its entanglement. The odd and even states vanish at the same value of field intensity.
文摘The Bactrocera oleae Rossi fly is the most important olive pest. It is of major economic importance in the olive production area of Essaouira, where weather conditions are optimal for the conduct of the various stages of its life cycle. The lack of phytosanitary treatments worsens this situation. The development of the larval stages and different generations are related to the phenological stages of the olive and are controlled by changes in habitat conditions. Trapping of adult males by Deltas traps baited with sex pheromone, at the four study sites, has identified some characteristics of the evolution of the adult populations’ flight dynamics. Our main results show a decreasing gradient of early emergences of different stages from the coast to the continental areas as well as the absence of the summer generation at the inner station. Soil analysis in the two stations showed that the hypogenous pupae wintering in the soil survive until June. Knowledge of the factors involved in the bio-ecology of the olive fly and the phenology of the host allows the elaboration of monitoring/ warning calendars, and phytosanitary measures in order to establish an IPM program adapted to the requirements of olive orchards in the region.
文摘Worldwide, large studies have shown that the menopause is mainly associated with substantial changes in body composition that result in an increase in waist circumference, fat accumulation and specially weight gain. This overweight could be exacerbated by fat intake. Thus, this study was planned to evaluate the impact of the consumption of olive and argane oils on anthropometric profile and body composition of postmenopausal women. The nutritional intervention was conducted over a period of eight weeks, involving daily consumption of 25 mL of argane oil The anthropometric profile （weight, height and body mass index or olive oil in 151 postmenopausal women （55.49 ± 6.18 years old）. （BMI）） and body composition （fat mass （FM） and lean mass （LM）） were determined at 0 week （baseline）, and after the 4th and 8th weeks of nutritional intervention. Results clearly demonstrated that argane oil or olive oil consumption did not affect the anthropometric parameters and the body composition of postmenopausal women. Thus, argane and/or olive oils＇ regular diet does not lead to weight gain, and postmenopausal women could benefit from their impact on health for a better quality of life and to overcome all menopause associated problems. A longer period of nutritional intervention is required to confirm the trend down that was recorded.
文摘In organic lettuce cultivation,snails can cause great economic loss.There is a lack of effective control methods for these molluscs.This work is focused on the development of a new agricultural plastic mulch material based on low density polyethylene(LDPE),as it is the most widely used polymer in plasticulture.The objective was to develop a new bio-based plastic mulch material that is insect repellent and anti-biofilm by incorporating a bioactive substance into the conventional formulation of the material.A new plastic mulching film made of 0.1%cade oil as was produced using the extrusion process.Bioadhesion tests carried out with aqueous suspensions of Escherichia coli and Pseudomonas aeruginosa show that this material is endowed with anti-biofilm effects.This study will demonstrate how to act by repulsive effect to Helix aspersa against this devastating mollusk in salads culture.
