90 research outputs found

    QoS-VNS-CS: QoS constraints Core Selection Algorithm based on Variable Neighborhood Search Algorithm

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    Within the development of network multimedia technology, more and more real-time multimedia applications arrive with the need to transmit information using multicast communication. Multicast IP routing is an important topic, covering both theoretical and practical interest in different networks layers. In network layer, there are several multicast routing protocols using multicast routing trees different in the literature. However PIM-SM and CBT protocols remains the most used multicast routing protocols; they propose using a shared Core-based Tree CBT. This kind of tree provides efficient management of multicast path in changing group memberships, scalability and performance. The prime problem concerning construction of a shared tree is to determine the best position of the core. QoS-CS’s problem (QoS constraints core Selection) consists in choosing an optimal multicast router in the network as core of the Shared multicast Tree (CBT) within specified QoS constraints associated. The choice of this specific router, called RP in PIM-SM protocol and core in CBT protocol, affects the structure of multicast routing tree, and therefore influences performances of both multicast session and routing scheme. QoS-CS is an NP complete problem need to be solved through a heuristic algorithm, in this paper, we propose a new core Selection algorithm based on Variable Neighborhood Search algorithm and new CMP fitness function. Simulation results show that good performance is achieved in multicast cost, end-to-end delay, tree construction delay and others metrics

    Streptococcus pneumoniae carriage among healthy and sick pediatric patients before the generalized implementation of the 13-valent pneumococcal vaccine in Morocco from 2010 to 2011

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    Nasopharyngeal carriage studies provide insights into the local prevalence of circulating pneumococcal serotypes. These data are critical to vaccination monitoring, as they allow for the prediction and assessment of impact. Very little data are available on the carriage of pneumococcal serotypes in Morocco. Here, we describe the prevalence of Streptococcus pneumoniae carriage and serotype distribution among 697 pediatric patients with ages ranging from 2 to 59 months who were admitted to a Moroccan hospital with severe pneumonia, as well as 195 healthy infants and young children who were recruited at a vaccination clinic. Carriage rates were 40.5% (79/195) for healthy children and 22.8% (159/697) for sick children. The most commonly observed circulating serotypes included 6A, 6B and 19F, all of which are included in the current 13-valent anti-pneumococcal conjugate vaccine that was recently introduced in Morocco. Monitoring of circulating serotypes remains necessary after vaccine introduction to assess whether serotype replacement is occurring

    Deep Brain Stimulation in Moroccan Patients With Parkinson's Disease: The Experience of Neurology Department of Rabat

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    Introduction: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is known as a therapy of choice of advanced Parkinson's disease. The present study aimed to assess the beneficial and side effects of STN DBS in Moroccan Parkinsonian patients.Material and Methods: Thirty five patients underwent bilateral STN DBS from 2008 to 2016 in the Rabat University Hospital. Patients were assessed preoperatively and followed up for 6 to 12 months using the Unified Parkinson's Disease Rating Scale in four conditions (stimulation OFF and ON and medication OFF and ON), the levodopa-equivalent daily dose (LEDD), dyskinesia and fluctuation scores and PDQ39 scale for quality of life (QOL). Postoperative side effects were also recorded.Results: The mean age at disease onset was 42.31 ± 7.29 years [28–58] and the mean age at surgery was 54.66 ± 8.51 years [34–70]. The median disease duration was 11.95 ± 4.28 years [5–22]. Sixty-three percentage of patients were male. 11.4% of patients were tremor dominant while 45.71 showed akinetic-rigid form and 42.90 were classified as mixed phenotype. The LEDD before surgery was 1200 mg/day [800-1500]. All patients had motor fluctuations whereas non-motor fluctuations were present in 61.80% of cases. STN DBS decreased the LEDD by 51.72%, as the mean LEDD post-surgery was 450 [188-800]. The UPDRS-III was improved by 52.27%, dyskinesia score by 66.70% and motor fluctuations by 50%, whereas QOL improved by 27.12%. Post-operative side effects were hypophonia (2 cases), infection (3 cases), and pneumocephalus (2 cases).Conclusion: Our results showed that STN DBS is an effective treatment in Moroccan Parkinsonian patients leading to a major improvement of the most disabling symptoms (dyskinesia, motor fluctuation) and a better QOL

    Les germènes : sources d'hétérocycles organo-matalliques

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    This thesis is a contribution to the reactivity study of germanium doubly-bonded derivatives. During this work, we have been successful in the synthesis of the first stable cyclic germanium aminoester and of its phosphorus analogue. We showed, via some other examples, that owing to its unique structure, the germene Mes2Ge=CR2 (Mes = 2,4,6- trimethylphenyl, CR2 = fluorenylidene) can behave, depending on the nitrile, as a base, a 1,2- dipolar reactant or an heterodiene. This ambivalent character proves its rich synthetic potential. This germene is an hyperreactive compound : thus, many heterocycles displaying various structures, difficult to obtain by other routes, have been prepared by [2+2] or [2+3] cycloaddition reactions with unsaturated species such as isocyanates and isothiocyanates, nitroalkyl derivatives and carbon disulfide. Our results show that this germanium-carbon doubly-bonded compound is a powerful buiding block in heterocyclic and organometallic chemistry.Le travail développé dans ce mémoire est une contribution à l'étude de la réactivité de dérivés doublement liés du germanium. Nous avons réussi au cours de ce travail, d'une part à synthétiser le premier aminoester a-germanié cyclique stable ainsi que son homologue phosphoré; nous avons montré d'autre part à travers quelques exemples, que grâce à sa structure originale, le germène Mes2Ge=CR2 (Mes = 2,4,6-triméthylphényl, CR2 = fluorénylidène) peut se comporter, en fonction des nitriles qui lui sont confrontés, comme une base, un réactif dipolaire 1,2 ou un hétérodiène. Cette ambivalence démontre le riche potentiel du germène comme synthon. Ce germène est un composé hyperréactif: ainsi de nombreux hétérocycles de structure inédite - difficilement accessibles par d'autres voies - ont été obtenus par des réactions de cycloaddition [2+2] ou [2+3] entre ce dernier et divers substrats insaturés tels que les isocyanates et isothiocyanates, les nitroalkyles et le disulfure de carbone. Nos résultats montrent donc que ce dérivé à double liaison germanium-carbone constitue une "brique moléculaire" de choix en synthèse organométallique et hétérocyclique
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