The Experts below are selected from a list of 126 Experts worldwide ranked by ideXlab platform

Pierre Faure - One of the best experts on this subject based on the ideXlab platform.

  • impact of clay mineral wood sawdust or root organic matter on the bacterial and fungal community structures in two aged pah contaminated soils
    Environmental Science and Pollution Research, 2015
    Co-Authors: Aurelie Cebron, Thierry Beguiristain, Jeanne Bongouadevisme, Jeremie Denonfoux, Pierre Faure
    Abstract:

    The high organic pollutant concentration of aged polycyclic aromatic hydrocarbon (PAH)-contaminated wasteland soils is highly recalcitrant to biodegradation due to its very low bioAvailability. In such soils, the microbial community is well adapted to the pollution, but the microbial activity is limited by nutrient Availability. Management strategies could be applied to modify the soil microbial functioning as well as the PAH contamination through various amendment types. The impact of amendment with clay minerals (montmorillonite), wood sawdust and organic matter plant roots on microbial community structure was investigated on two aged PAH-contaminated soils both in laboratory and 1-year on-site pot experiments. Total PAH content (sum of 16 PAHs of the US-EPA list) and polar polycyclic aromatic compounds (pPAC) were monitored as well as the available PAH fraction using the Tenax method. The bacterial and fungal community structures were monitored using fingerprinting thermal gradient gel electrophoresis (TTGE) method. The abundance of bacteria (16S rRNA genes), fungi (18S rRNA genes) and PAH degraders (PAH-ring hydroxylating dioxygenase and catechol dioxygenase genes) was followed through qPCR assays. Although the treatments did not modify the total and available PAH content, the microbial community density, structure and the PAH degradation potential changed when fresh organic matter was provided as sawdust and under rhizosphere influence, while the clay mineral only increased the percentage of catechol-1,2-dioxygenase genes. The abundance of bacteria and fungi and the percentage of fungi relative to bacteria were enhanced in soil samples supplemented with wood sawdust and in the plant rhizospheric soils. Two distinct fungal populations developed in the two soils supplemented with sawdust, i.e. fungi related to Chaetomium and Neurospora genera and Brachyconidiellopsis and Pseudallescheria genera, in H and NM soils respectively. Wood sawdust amendment favoured the development of PAH-degrading bacteria holding Gram-negative PAH-ring hydroxylating dioxygenase, catechol-1,2-dioxygenase and catechol-2,3-dioxygenase genes. Regarding the total community structure, bacteria closely related to Thiobacillus (β-Proteobacteria) and Steroidobacter (γ-Proteobacteria) genera were favoured by wood sawdust amendment. In both soils, plant rhizospheres induced the development of fungi belonging to Ascomycota and related to Alternaria and Fusarium genera. Bacteria closely related to Luteolibacter (Verrucomicrobia) and Microbacterium (Actinobacteria) were favoured in alfalfa and ryegrass rhizosphere.

Jeanne Bongouadevisme - One of the best experts on this subject based on the ideXlab platform.

  • impact of clay mineral wood sawdust or root organic matter on the bacterial and fungal community structures in two aged pah contaminated soils
    Environmental Science and Pollution Research, 2015
    Co-Authors: Aurelie Cebron, Thierry Beguiristain, Jeanne Bongouadevisme, Jeremie Denonfoux, Pierre Faure
    Abstract:

    The high organic pollutant concentration of aged polycyclic aromatic hydrocarbon (PAH)-contaminated wasteland soils is highly recalcitrant to biodegradation due to its very low bioAvailability. In such soils, the microbial community is well adapted to the pollution, but the microbial activity is limited by nutrient Availability. Management strategies could be applied to modify the soil microbial functioning as well as the PAH contamination through various amendment types. The impact of amendment with clay minerals (montmorillonite), wood sawdust and organic matter plant roots on microbial community structure was investigated on two aged PAH-contaminated soils both in laboratory and 1-year on-site pot experiments. Total PAH content (sum of 16 PAHs of the US-EPA list) and polar polycyclic aromatic compounds (pPAC) were monitored as well as the available PAH fraction using the Tenax method. The bacterial and fungal community structures were monitored using fingerprinting thermal gradient gel electrophoresis (TTGE) method. The abundance of bacteria (16S rRNA genes), fungi (18S rRNA genes) and PAH degraders (PAH-ring hydroxylating dioxygenase and catechol dioxygenase genes) was followed through qPCR assays. Although the treatments did not modify the total and available PAH content, the microbial community density, structure and the PAH degradation potential changed when fresh organic matter was provided as sawdust and under rhizosphere influence, while the clay mineral only increased the percentage of catechol-1,2-dioxygenase genes. The abundance of bacteria and fungi and the percentage of fungi relative to bacteria were enhanced in soil samples supplemented with wood sawdust and in the plant rhizospheric soils. Two distinct fungal populations developed in the two soils supplemented with sawdust, i.e. fungi related to Chaetomium and Neurospora genera and Brachyconidiellopsis and Pseudallescheria genera, in H and NM soils respectively. Wood sawdust amendment favoured the development of PAH-degrading bacteria holding Gram-negative PAH-ring hydroxylating dioxygenase, catechol-1,2-dioxygenase and catechol-2,3-dioxygenase genes. Regarding the total community structure, bacteria closely related to Thiobacillus (β-Proteobacteria) and Steroidobacter (γ-Proteobacteria) genera were favoured by wood sawdust amendment. In both soils, plant rhizospheres induced the development of fungi belonging to Ascomycota and related to Alternaria and Fusarium genera. Bacteria closely related to Luteolibacter (Verrucomicrobia) and Microbacterium (Actinobacteria) were favoured in alfalfa and ryegrass rhizosphere.

Aurelie Cebron - One of the best experts on this subject based on the ideXlab platform.

  • impact of clay mineral wood sawdust or root organic matter on the bacterial and fungal community structures in two aged pah contaminated soils
    Environmental Science and Pollution Research, 2015
    Co-Authors: Aurelie Cebron, Thierry Beguiristain, Jeanne Bongouadevisme, Jeremie Denonfoux, Pierre Faure
    Abstract:

    The high organic pollutant concentration of aged polycyclic aromatic hydrocarbon (PAH)-contaminated wasteland soils is highly recalcitrant to biodegradation due to its very low bioAvailability. In such soils, the microbial community is well adapted to the pollution, but the microbial activity is limited by nutrient Availability. Management strategies could be applied to modify the soil microbial functioning as well as the PAH contamination through various amendment types. The impact of amendment with clay minerals (montmorillonite), wood sawdust and organic matter plant roots on microbial community structure was investigated on two aged PAH-contaminated soils both in laboratory and 1-year on-site pot experiments. Total PAH content (sum of 16 PAHs of the US-EPA list) and polar polycyclic aromatic compounds (pPAC) were monitored as well as the available PAH fraction using the Tenax method. The bacterial and fungal community structures were monitored using fingerprinting thermal gradient gel electrophoresis (TTGE) method. The abundance of bacteria (16S rRNA genes), fungi (18S rRNA genes) and PAH degraders (PAH-ring hydroxylating dioxygenase and catechol dioxygenase genes) was followed through qPCR assays. Although the treatments did not modify the total and available PAH content, the microbial community density, structure and the PAH degradation potential changed when fresh organic matter was provided as sawdust and under rhizosphere influence, while the clay mineral only increased the percentage of catechol-1,2-dioxygenase genes. The abundance of bacteria and fungi and the percentage of fungi relative to bacteria were enhanced in soil samples supplemented with wood sawdust and in the plant rhizospheric soils. Two distinct fungal populations developed in the two soils supplemented with sawdust, i.e. fungi related to Chaetomium and Neurospora genera and Brachyconidiellopsis and Pseudallescheria genera, in H and NM soils respectively. Wood sawdust amendment favoured the development of PAH-degrading bacteria holding Gram-negative PAH-ring hydroxylating dioxygenase, catechol-1,2-dioxygenase and catechol-2,3-dioxygenase genes. Regarding the total community structure, bacteria closely related to Thiobacillus (β-Proteobacteria) and Steroidobacter (γ-Proteobacteria) genera were favoured by wood sawdust amendment. In both soils, plant rhizospheres induced the development of fungi belonging to Ascomycota and related to Alternaria and Fusarium genera. Bacteria closely related to Luteolibacter (Verrucomicrobia) and Microbacterium (Actinobacteria) were favoured in alfalfa and ryegrass rhizosphere.

Thierry Beguiristain - One of the best experts on this subject based on the ideXlab platform.

  • impact of clay mineral wood sawdust or root organic matter on the bacterial and fungal community structures in two aged pah contaminated soils
    Environmental Science and Pollution Research, 2015
    Co-Authors: Aurelie Cebron, Thierry Beguiristain, Jeanne Bongouadevisme, Jeremie Denonfoux, Pierre Faure
    Abstract:

    The high organic pollutant concentration of aged polycyclic aromatic hydrocarbon (PAH)-contaminated wasteland soils is highly recalcitrant to biodegradation due to its very low bioAvailability. In such soils, the microbial community is well adapted to the pollution, but the microbial activity is limited by nutrient Availability. Management strategies could be applied to modify the soil microbial functioning as well as the PAH contamination through various amendment types. The impact of amendment with clay minerals (montmorillonite), wood sawdust and organic matter plant roots on microbial community structure was investigated on two aged PAH-contaminated soils both in laboratory and 1-year on-site pot experiments. Total PAH content (sum of 16 PAHs of the US-EPA list) and polar polycyclic aromatic compounds (pPAC) were monitored as well as the available PAH fraction using the Tenax method. The bacterial and fungal community structures were monitored using fingerprinting thermal gradient gel electrophoresis (TTGE) method. The abundance of bacteria (16S rRNA genes), fungi (18S rRNA genes) and PAH degraders (PAH-ring hydroxylating dioxygenase and catechol dioxygenase genes) was followed through qPCR assays. Although the treatments did not modify the total and available PAH content, the microbial community density, structure and the PAH degradation potential changed when fresh organic matter was provided as sawdust and under rhizosphere influence, while the clay mineral only increased the percentage of catechol-1,2-dioxygenase genes. The abundance of bacteria and fungi and the percentage of fungi relative to bacteria were enhanced in soil samples supplemented with wood sawdust and in the plant rhizospheric soils. Two distinct fungal populations developed in the two soils supplemented with sawdust, i.e. fungi related to Chaetomium and Neurospora genera and Brachyconidiellopsis and Pseudallescheria genera, in H and NM soils respectively. Wood sawdust amendment favoured the development of PAH-degrading bacteria holding Gram-negative PAH-ring hydroxylating dioxygenase, catechol-1,2-dioxygenase and catechol-2,3-dioxygenase genes. Regarding the total community structure, bacteria closely related to Thiobacillus (β-Proteobacteria) and Steroidobacter (γ-Proteobacteria) genera were favoured by wood sawdust amendment. In both soils, plant rhizospheres induced the development of fungi belonging to Ascomycota and related to Alternaria and Fusarium genera. Bacteria closely related to Luteolibacter (Verrucomicrobia) and Microbacterium (Actinobacteria) were favoured in alfalfa and ryegrass rhizosphere.

Kishor S. Trivedi - One of the best experts on this subject based on the ideXlab platform.

  • Modeling and analysis of software rejuvenation in a server virtualized system
    2010 IEEE Second International Workshop on Software Aging and Rejuvenation, 2010
    Co-Authors: Fumio Machida, Dong Seong Kim, Kishor S. Trivedi
    Abstract:

    As server virtualization is used as an essential software infrastructure of various software services such as cloud computing, Availability Management of server virtualized system is becoming more significant. Although time-based software rejuvenation is useful to postpone/prevent failures due to software aging in a server virtualized system, the rejuvenation schedules for virtual machine (VM) and virtual machine monitor (VMM) need to be determined in a proper way for the VM Availability, since VMM rejuvenation affects VMs running on the VMM. This paper presents analytic models using stochastic reward nets for three time-based rejuvenation techniques of VMM; (i) Cold-VM rejuvenation in which all VMs are shut down before the VMM rejuvenation, (ii) Warm-VM rejuvenation in which all VMs are suspended before the VMM rejuvenation and (iii) Migrate-VM rejuvenation in which all VMs are moved to the other host server during the VMM rejuvenation. We compare the three techniques in terms of steady-state Availability and the number of transactions lost in a year. We find the optimal combination of rejuvenation trigger intervals for each rejuvenation technique by a gradient search method. The numerical analysis shows the interesting result that Warm-VM rejuvenation does not always outperform Cold-VM rejuvenation in terms of steady-state Availability depending on rejuvenation trigger intervals. Migrate-VM rejuvenation is better than the other two as long as live VM migration rate is large enough and the other host server has a capacity to accept the migrated VM.

  • model based approach for autonomic Availability Management
    Lecture Notes in Computer Science, 2006
    Co-Authors: Kesari Mishra, Kishor S. Trivedi
    Abstract:

    As increasingly complex computer systems have started playing a controlling role in all aspects of modern life, system Availability and associated downtime of technical systems have acquired critical importance. Losses due to system downtime have risen manifold and become wide-ranging. Even though the component level Availability of hardware and software has increased considerably, system wide Availability still needs improvement as the heterogeneity of components and the complexity of interconnections has gone up considerably too. As systems become more interconnected and diverse, architects are less able to anticipate and design for every interaction among components, leaving such issues to be dealt with at runtime. Therefore, in this paper, we propose an approach for autonomic Management of system Availability, which provides real-time evaluation, monitoring and Management of the Availability of systems in critical applications. A hybrid approach is used where analytic models provide the behavioral abstraction of components/subsystems, their interconnections and dependencies and statistical inference is applied on the data from real time monitoring of those components and subsystems, to parameterize the system Availability model. The model is solved online (that is, in real time) so that at any instant of time, both the point as well as the interval estimates of the overall system Availability are obtained by propagating the point and the interval estimates of each of the input parameters, through the system model. The online monitoring and estimation of system Availability can then lead to adaptive online control of system Availability.