123 research outputs found

    An efficient partial data aggregation scheme in WSNs

    Get PDF
    Highly accurate event detection makes Wireless Sensor Networks popular for real time monitoring applications. Wireless sensor systems that monitor physical and environmental conditions are expected to be deployed with high density, a situation which leads to spatial correlations and redundancy of the collected data. Eliminating these redundancies extends the network lifetime by reducing energy consumption and enhances the velocity of transmitting emergency and periodic messages. In this work, we focus on the scenario where sensors are grouped into clusters. Each Cluster Head (CH) receives samplings from its Cluster Members (CMs), and decides when it should stop sampling, and starts transmitting the resulting packet from the aggregation process in order to reduce the end-to-end delay and ensure the accuracy of the transmitted data. To this end, we propose a cluster based aggregation scheme which determines, at the CH level, the best timing for achieving a short delay, and provides an efficient buffer management strategy for maintaining low energy consumption. Evaluation results based on simulations show that our scheme achieves a good trade-off between energy consumption and end-to-end delay

    Pulsed 86Sr-labeling and NanoSIMS imaging to study coral biomineralization at ultra-structural length scales

    Get PDF
    A method to label marine biocarbonates is developed based on a concentration enrichment of a minor stable isotope of a trace element that is a natural component of seawater, resulting in the formation of biocarbonate with corresponding isotopic enrichments. This biocarbonate is subsequently imaged with a NanoSIMS ion microprobe to visualize the locations of the isotopic marker on sub-micrometric length scales, permitting resolution of all ultra-structural details. In this study, a scleractinian coral, Pocillopora damicornis, was labeled 3 times with 86Sr-enhanced seawater for a period of 48h with 5days under normal seawater conditions separating each labeling event. Two non-specific cellular stress biomarkers, glutathione-S-transferase activity and porphyrin concentration plus carbonic anhydrase, an enzymatic marker involved in the physiology of carbonate biomineralization, as well as unchanged levels of zooxanthellae photosynthesis efficiency indicate that coral physiological processes are not affected by the 86Sr-enhancement. NanoSIMS images of the 86Sr/44Ca ratio in skeleton formed during the experiment allow for a determination of the average extension rate of the two major ultra-structural components of the coral skeleton: Rapid Accretion Deposits are found to form on average about 4.5 times faster than Thickening Deposits. The method opens up new horizons in the study of biocarbonate formation because it holds the potential to observe growth of calcareous structures such as skeletons, shells, tests, spines formed by a wide range of organisms under essentially unperturbed physiological condition

    Etude comparative des huiles essentielles de six variétés des nouvelles obtentions d’agrumes cultivées au Maroc

    Get PDF
    In this research, the essential oils of six INRA’s citrus varieties, which are mandarines El Marzaka, El Mahdia, El Gharabaouia, El Hamra, El Maamoura and orange Shemsia were compared and analyzed. For this purpose, the oil yield, chemical composition, antioxidant and antimicrobial activity were investigated. The extraction was carried out by hydro-distillation. The highest essential oil yield was obtained for Shemsia (5,63%/ DW). The main components of essential oils were identified by GC-MS and their antioxidant activity was determined by DPPH method. The major component of essential oils is D-Limonene, and the highest antioxidant activity was obtained for Shemsia essential oil (24.02%). Antifungal activity was detected in all varieties and the highest value was identified in El Maamoura, while antibacterial activity was not distinguished. From the obtained results, we note that the essential oils of El Maamoura can be valued as a fungicide in agriculture or in medical field. in addition, El Hamra, can be used in Solar cream industry.Les huiles essentielles de six variétés d’agrumes obtenues de l’INRA du Maroc, et qui sont : les mandarines El Marzaka, El Mahdia, El Gharabaouia, El Hamra, El Maamoura et l’orange Shemsia ont été comparées et analysées. La comparaison a été effectuée en termes de rendement, de composition chimique, d’activité antioxydante et d’activité antimicrobienne de ces huiles essentielles. L’extraction a été effectuée par hydro-distillation. Le rendement en huile essentielle le plus élevé a été obtenu chez la variété Shemsia (5,63%/PS). Les principaux composants des huiles essentielles ont été identifiés par CPG-MS et leur activité antioxydante a été déterminée en testant la capacité de piégeage des radicaux libres par DPPH. Le composant majeur des huiles essentielles est le D-Limonène et la plus haute activité antioxydante a été obtenue pour l'huile essentielle d’El Maamoura (24,02%). L'activité antifongique a été détectée chez toutes les variétés et la valeur la plus élevée a été repérée chez El Maamoura, alors que l'activité antibactérienne n'a été détectée chez aucune variété. À partir des résultats obtenus, nous constatons que l’huile essentielle de la mandarine El Maamoura peut être valorisée sous forme de fongicide dans le domaine d’agriculture ou dans le domaine médical. En plus, la variété El Hamra peut être incorporée dans l’industrie de la fabrication des crèmes solaires

    Prise en charge du couple mère enfant de la varicelle pendant la grossesse

    Get PDF
    La varicelle est une maladie généralement bénigne chez l’enfant, cependant l’atteinte de l’adulte est potentiellement grave et son association à la grossesse expose la mère et le nouveau né à des risques de complications plus redoutables.La prise en charge multidisciplinaire associant obstétricien, biologiste et pédiatre est indispensable pour limiter les effets délétères de l’infection par la varicelle pendant la grossesse.Nous rapportons dans cet article les approches thérapeutiques actuellement proposées pour la prise en charge anté et péripartum du couple mère-enfant en cas d’infection par la varicelle pendant la grossesse et nous proposons des conduites visant à atténuer les complications maternelles

    Pulsed 86Sr-labeling and NanoSIMS imaging to study coral biomineralization at ultra-structural length scales

    Get PDF
    A method to label marine biocarbonates is developed based on a concentration enrichment of a minor stable isotope of a trace element that is a natural component of seawater, resulting in the formation of biocarbonate with corresponding isotopic enrichments. This biocarbonate is subsequently imaged with a NanoSIMS ion microprobe to visualize the locations of the isotopic marker on sub-micrometric length scales, permitting resolution of all ultra-structural details. In this study, a scleractinian coral, Pocillopora damicornis, was labeled 3 times with Sr-86-enhanced seawater for a period of 48 h with 5 days under normal seawater conditions separating each labeling event. Two non-specific cellular stress biomarkers, glutathione-S-transferase activity and porphyrin concentration plus carbonic anhydrase, an enzymatic marker involved in the physiology of carbonate biomineralization, as well as unchanged levels of zooxanthellae photosynthesis efficiency indicate that coral physiological processes are not affected by the Sr-86-enhancement. NanoSIMS images of the Sr-86/Ca-44 ratio in skeleton formed during the experiment allow for a determination of the average extension rate of the two major ultra-structural components of the coral skeleton: Rapid Accretion Deposits are found to form on average about 4.5 times faster than Thickening Deposits. The method opens up new horizons in the study of biocarbonate formation because it holds the potential to observe growth of calcareous structures such as skeletons, shells, tests, spines formed by a wide range of organisms under essentially unperturbed physiological conditions

    Gastrointestinal decontamination in the acutely poisoned patient

    Get PDF
    ObjectiveTo define the role of gastrointestinal (GI) decontamination of the poisoned patient.Data sourcesA computer-based PubMed/MEDLINE search of the literature on GI decontamination in the poisoned patient with cross referencing of sources.Study selection and data extractionClinical, animal and in vitro studies were reviewed for clinical relevance to GI decontamination of the poisoned patient.Data synthesisThe literature suggests that previously, widely used, aggressive approaches including the use of ipecac syrup, gastric lavage, and cathartics are now rarely recommended. Whole bowel irrigation is still often recommended for slow-release drugs, metals, and patients who "pack" or "stuff" foreign bodies filled with drugs of abuse, but with little quality data to support it. Activated charcoal (AC), single or multiple doses, was also a previous mainstay of GI decontamination, but the utility of AC is now recognized to be limited and more time dependent than previously practiced. These recommendations have resulted in several treatment guidelines that are mostly based on retrospective analysis, animal studies or small case series, and rarely based on randomized clinical trials.ConclusionsThe current literature supports limited use of GI decontamination of the poisoned patient
    • …
    corecore