24 research outputs found

    Total quality management in small and medium enterprises Prospects and challenges

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    تعتبر المؤسسات الصغيرة والمتوسطة المحرك الأساسي لاقتصاد أي دولة بالنظر لمساهمتها الكبيرة في تحقيق النمو الاقتصادي وزيادة الناتج الوطني والتقليل من البطالة، لكن الأمر الذي أصبح يشكل هاجساً لأصحاب ومدراء هذه المؤسسات هو المنافسة الشديدة التي تواجهها هذه المؤسسات سواءً على المستوى المحلي أو العالمي والتي أصبحت تهدد بقاءها واستمرارها في نشاطها، لذا كان لزاماً عليهم تبني مفاهيم إدارية جديدة قادرة على زيادة القدرة التنافسية لهذه المؤسسات، والتي تأتي في مقدمتها إدارة الجودة الشاملة التي تعتبر المدخل لكل عمليات التحسين والتطوير بالمؤسسة. SME’s are considered the main engine of the economy of any country, given the large contribution to economic growth and increase national output and reduce unemployment, but which has become a concern for owners and managers of these institutions is intense competition faced by these institutions, whether at the local or global level that has become threaten its survival and it continues to operate, so it was incumbent on them to adopt new management concepts able to increase the competitiveness of these institutions, which come in the forefront of the overall quality, which is the entrance of each improvement operations and development management of the institution

    Modeling Subjective Symptoms Related to Micro-Hydrargyrism in a Population of Moroccan Dentists

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    BACKGROUND፡ The ability of mercury to deposit throughout the body and alter a wide range of molecular and cellular pathways results in a polymorphic and complex clinical phenotype with over 250 possible symptoms. However, some of them are recurrently cited as evoking chronic mercury poisoning. In this light, dentists users of dental amalgams are chronically exposed to mercury so that in-depth epidemiological investigations and adapted statistical methods are required to highlight adverse effects of this exposure.METHODS: In order to study the health impact of the occupational mercury exposure in a population of liberal dentists practicing in two Moroccan regions, a list of eighteen subjective symptoms commonly associated with micro-hydrargyrism was drawn up. Then, seven statisctical models adapted to count data were fitted. Finally, three methods were used to compare their relative performance in order to choose the most appropriate one.RESULTS: The adopted logical path, from the response variable selection till models’ comparison, led us to lean towards quasi- Poisson regression as the best way to predict the number of symptoms declared by dentists according to mercury exposure.CONCLUSIONS: Interpretation of the selected model allowed us to conclude that the reduction of dental amalgam use allows the reduction of subjective symptoms related to mercury exposure

    Reaction of some rapeseed (Brassica napus L.) genotypes to different drought stress levels during germination and seedling growth stages☆

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    Drought is a major abiotic stress that affects seed germination and plant growth in arid and semi-arid regions. Rapeseed is an oilseed crop adapted to Mediterranean area; however, it is reported that it is sensitive to water stress occurring during seed germination. In this study, we investigated how seed germination and early seedling growth of six rapeseed genotypes were influenced by different water stress levels. In addition to the control (absence of drought stress), three drought levels were simulated using three osmotic potentials of polyethylene glycol (PEG-6000), −9, −10 and −11 bars. A completely randomized design with three replications was used for this experiment. Germination percentage (GP), shoot length (SL), root length (RL), shoot elongation rate (SER) and root elongation rate (RER) were determined to evaluate the genotypes response to PEG-induced drought stress. Results showed drought stress, genotype and interaction stress × genotype had a significant effect on the studied parameters. GP decreased with the increase in stress level. The genotype ‛Nap9’ was the most interesting, having the highest GP values, namely 63.33, 62.67 and 28% under the stress levels −9, −10 and −11 bars, respectively. The genotype ‛H2M-5’, which ranked second with respect to this parameter, was statistically comparable to ‛Nap9’. Also, SL, RL, SER and RER decreased with the increase in drought stress level. However, the studied genotypes reacted differently to various water stress levels. Once again, the genotype ‛H2M-5’ exhibited the highest average RL and RER under all drought levels. Particularly, for severe drought conditions (−11 bars), ‛H2M-5’ had an average RL of 1.54 cm and RER of 0.36 cm/d. Field evaluation under controlled conditions is needed to confirm findings of the present experiment. The mutant ‛H2M-5’ could be a valuable and promising germplasm for developing a performant and adapted variety to be designed for harsh environments particularly characterized by early drought coinciding with germination and seedling growth stages

    Germination and Seedling Growth of a Set of Rapeseed (Brassica napus) Varieties under Drought Stress Conditions

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    Drought stress is one of the major abiotic factors affecting seed germination and plant growth especially in arid and semi-arid regions. In this study, we investigated the effects of drought stress on seed germination and seedling growth of five varieties of rapeseed. Seven drought stress levels of zero (control), -3, -5, -7, -9, -11 and -13 bars were performed using polyethylene glycol-6000 (PEG-6000). A completely randomized design with three replications was used for this experiment. Germination percentage (GP), germination rate (GR), mean germination time (MGT), root length (RL) and shoot length (SL) were measured to evaluate the varieties response to PEG-induced drought stress. Drought stress, variety and the interaction drought × variety had a significant effect on all studied parameters. GP and GR decreased with the increase in stress level, while MGT increased. There were no seeds germinated for all varieties at -11 bars and -13 bars. Shoot length decreased with increasing drought stress but different varieties show different performance under stress environment. Root length decreased with increasing level of severe drought stress. However, the presence of moderate drought stress could even improve the root growth of the investigated varieties. The varieties ‘INRA-CZH2' and ‘INRA-CZH3' exhibited the highest germination percentage and the best early seedling growth. Thus, they could be recommended for environments with early cropping cycle drought

    Procédé de purification et de concentration des terres rares à partir du phosphogypse

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    La présente invention concerne un procédé de purification et de concentration des terres rares contenues dans du phosphogypse, caractérisé en ce qu'il comprend les étapes suivantes : à partir d'un phosphogypse, a) Lixiviation du phosphogypse par une solution d'un ou plusieurs acides forts choisis parmi : l'acide sulfurique, l'acide nitrique, et l'acide chlorhydrique, pour obtenir un mélange de lixiviation comprenant une phase liquide formée d'une solution de lixiviation contenant des terres rares issus du phosphogypse et l'acide de lixiviation, et d'une phase solide comprenant le phosphogypse, b) Ajout au phosphogypse d'un agent oxydant pour favoriser le passage des terres rares du phosphogypse dans la solution de lixiviation, et/ou d'un agent réducteur pour réduire la solubilité des impuretés minérales contenues dans la solution de lixiviation afin de permettre leur passage de la solution de lixiviation dans la phase solide, c) Séparation de la phase liquide enrichie en terres rares et appauvrie en impuretés minérales, et de la phase solide enrichie en impuretés minérales

    Procédé de purification et de concentration des terres rares à partir du phosphogypse

    No full text
    La présente invention concerne un procédé de purification et de concentration des terres rares contenues dans du phosphogypse, caractérisé en ce qu'il comprend les étapes suivantes : à partir d'un phosphogypse, a) Lixiviation du phosphogypse par une solution d'un ou plusieurs acides forts choisis parmi : l'acide sulfurique, l'acide nitrique, et l'acide chlorhydrique, pour obtenir un mélange de lixiviation comprenant une phase liquide formée d'une solution de lixiviation contenant des terres rares issus du phosphogypse et l'acide de lixiviation, et d'une phase solide comprenant le phosphogypse, b) Ajout au phosphogypse d'un agent oxydant pour favoriser le passage des terres rares du phosphogypse dans la solution de lixiviation, et/ou d'un agent réducteur pour réduire la solubilité des impuretés minérales contenues dans la solution de lixiviation afin de permettre leur passage de la solution de lixiviation dans la phase solide, c) Séparation de la phase liquide enrichie en terres rares et appauvrie en impuretés minérales, et de la phase solide enrichie en impuretés minérales

    Separation of phosphoric acid sludge: effect of flocculation on settling and P2O5 recovery rates

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    Phosphoric acid sludge is one of the prominent problems in the phosphate industry. Its formation is co-occurred by considerable losses of P2O5 that affect the process performance. Management and valorization of this waste is a key issue. This work aimed to deal with this industrial concern by studying the influence of the flocculation on the sludge sedimentation and thus the P2O5 recovery rate. The flocculation tests were conducted in the presence of various types of anionic polymers. The effect of dosage, molecular weight, and type of flocculant were examined. The results indicated that all polymers showed settling performance improvement. And, the flocculant with the highest molecular weight (F1), showed the best settling performance with a pace of 3.3 cm/min and the lowest turbidity value of 40.4 NTU using a dosage of 5 ppm. Due to its high molecular weight, this polymer carries a polyelectrolyte bridging mechanism, which allows the absorbed polymer to move further away from the surface of the particle and then increases the particle radius, the number of collisions, and thus the particle size. However, for the P2O5 recovery rate, the sulfonic polymer (F5) was the best performer allowing recovery of 78.8% of the total mass of the sludge. F5 is weakly amphoteric. Polymers containing sulfonic acid groups are known to be inherently powerful than the carboxylic acid groups as they are stable due to their high energy barrier. According to the results, the flocculation increases the recovery of P2O5, which represents a profit of more than 30 kg of clarified phosphoric acid per 1 tone of sludge

    Reaction of some rapeseed (

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    Drought is a major abiotic stress that affects seed germination and plant growth in arid and semi-arid regions. Rapeseed is an oilseed crop adapted to Mediterranean area; however, it is reported that it is sensitive to water stress occurring during seed germination. In this study, we investigated how seed germination and early seedling growth of six rapeseed genotypes were influenced by different water stress levels. In addition to the control (absence of drought stress), three drought levels were simulated using three osmotic potentials of polyethylene glycol (PEG-6000), −9, −10 and −11 bars. A completely randomized design with three replications was used for this experiment. Germination percentage (GP), shoot length (SL), root length (RL), shoot elongation rate (SER) and root elongation rate (RER) were determined to evaluate the genotypes response to PEG-induced drought stress. Results showed drought stress, genotype and interaction stress × genotype had a significant effect on the studied parameters. GP decreased with the increase in stress level. The genotype ‛Nap9’ was the most interesting, having the highest GP values, namely 63.33, 62.67 and 28% under the stress levels −9, −10 and −11 bars, respectively. The genotype ‛H2M-5’, which ranked second with respect to this parameter, was statistically comparable to ‛Nap9’. Also, SL, RL, SER and RER decreased with the increase in drought stress level. However, the studied genotypes reacted differently to various water stress levels. Once again, the genotype ‛H2M-5’ exhibited the highest average RL and RER under all drought levels. Particularly, for severe drought conditions (−11 bars), ‛H2M-5’ had an average RL of 1.54 cm and RER of 0.36 cm/d. Field evaluation under controlled conditions is needed to confirm findings of the present experiment. The mutant ‛H2M-5’ could be a valuable and promising germplasm for developing a performant and adapted variety to be designed for harsh environments particularly characterized by early drought coinciding with germination and seedling growth stages

    Development and evaluation of diverse promising rapeseed (

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    Genetic variability is a prerequisite for any plant breeding program, and mutagenesis is a proven way of creating new variation within a crop germplasm. Novel genetic variability in rapeseed was induced by gamma rays, Ethyl Methane Sulphonate (EMS) and combined mutagen treatment, using various doses and concentrations. The objective was to evaluate and compare the obtained M2 mutants for important quantitative traits in two contrasted environments. Data on phenological, morphological and agronomic parameters were recorded. A large variability was observed and mutagenic treatments had a significant effect on all traits studied. Compared to control plants, mutant genotypes derived from seeds treated with low EMS concentrations during moderate time were earlier and characterized by a higher number of pods per plant. For high concentration of EMS during long time and for combinations of physical and chemical mutagens, a significant decrease in plant height and stature was noticed, as compared to control. Besides, plants derived from gamma rays-treated seeds exhibited the highest 1000-seed weight. The novel induced variability may be integrated in rapeseed breeding program as a new germplasm with improved agronomic traits. Particularly, EMS1-7-stable mutant may be exploited to develop efficiently and quickly a new rapeseed cultivar with some desirable traits. The present study highlights once more the possibility to bring novel genetic diversity for rapeseed desirable traits improvement through mutation breeding

    Impact of Pretreatment and Drying Factors on Chemical and Biochemical Attributes of Moroccan Thompson Seedless Grapes

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    Drying is a common technique in the agrifood industry, but insufficient control in the drying process can result in changes to the fruit’s appearance due to physiological damage during processing. The aim of this study was to investigate the impact of pretreatment and drying process parameters on Moroccan raisins’ quality and safety. The experimental levels of pretreatment factors (blanching, browning agents) and drying temperature were defined at the beginning. Subsequently, a 24-factorial design was employed to provide a simple and reliable model capable of relating directly the response factor (drying time, color intensity change (E∗), chromaticity (C∗), and browning rate) to the variables (NaOH concentration, antibrowning agent concentration, temperature, and relative humidity). All four parameters had a statistically considerable effect on studied responses. Blanching for 5 minutes at 1% of NaOH solution, using an appropriate concentration of antibrowning agent (5% Na2S2O5), and drying at 70°C with 30% of relative moisture can lead to better preservation of grapes’ appearance and quality (chromaticity (C∗) and color change (E∗)). Also, in these conditions, a lower browning rate (14.48%), a lower 5-hydroxymethylfurfural content (12.40 mg/100 g DW), and a higher level of polyphenols (135.79±13.17 mg GAE/100 g DW) and flavonoid content (57.81±3.08 mg Qeq/100 g DW) have been recorded while meeting international standards for SO2 content and microbial quality
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