2,029 research outputs found

    Load Balancing in SDN-Enabled WSNs Toward 6G IoE: Partial Cluster Migration Approach

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    The vision for the sixth-generation (6G) network involves the integration of communication and sensing capabilities in internet of everything (IoE), towards enabling broader interconnection in the devices of distributed wireless sensor networks (WSN). Moreover, the merging of SDN policies in 6G IoE-based WSNs i.e. SDN-enable WSN improves the network’s reliability and scalability via integration of sensing and communication (ISAC). It consists of multiple controllers to deploy the control services closer to the data plane for a speedy response through control messages. However, controller placement and load balancing are the major challenges in SDN-enabled WSNs due to the dynamic nature of data plane devices. To address the controller placement problem, an optimal number of controllers is identified using the articulation point method. Furthermore, a nature-inspired cheetah optimization algorithm is proposed for the efficient placement of controllers by considering the latency and synchronization overhead. Moreover, a load-sharing based control node migration (LS-CNM) method is proposed to address the challenges of controller load balancing dynamically. The LS-CNM identifies the overloaded controller and corresponding assistant controller with low utilization. Then, a suitable control node is chosen for partial migration in accordance with the load of the assistant controller. Subsequently, LS-CNM ensures dynamic load balancing by considering threshold loads, intelligent assistant controller selection, and real-time monitoring for effective partial load migration. The proposed LS-CNM scheme is executed on the open network operating system (ONOS) controller and the whole network is simulated in ns-3 simulator. The simulation results of the proposed LS-CNM outperform the state of the art in terms of frequency of controller overload, load variation of each controller, round trip time, and average delay

    High-pressure x-ray diffraction study of bulk and nanocrystalline PbMoO4

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    We studied the effects of high-pressure on the crystalline structure of bulk and nanocrystalline scheelite-type PbMoO4. We found that in both cases the compressibility of the materials is highly non-isotropic, being the c-axis the most compressible one. We also observed that the volume compressibility of nanocrystals becomes higher that the bulk one at 5 GPa. In addition, at 10.7(8) GPa we observed the onset of an structural phase transition in bulk PbMoO4. The high-pressure phase has a monoclinic structure similar to M-fergusonite. The transition is reversible and not volume change is detected between the low- and high-pressure phases. No additional structural changes or evidence of decomposition are found up to 21.1 GPa. In contrast nanocrystalline PbMoO4 remains in the scheelite structure at least up to 16.1 GPa. Finally, the equation of state for bulk and nanocrystalline PbMoO4 are also determined.Comment: 18 pages, 4 figure

    Plant genetic resources in India: management and utilization

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    Plant genetic resources (PGR) are the foundation of agriculture as well as food and nutritional security. The ICAR-NBPGR is the nodal institution at national level for management of PGR in India under the umbrella of Indian Council of Agricultural Research (ICAR), New Delhi. India being one of the gene-rich countries faces a unique challenge of protecting its natural heritage while evolving mutually beneficial strategies for germplasm exchange with other countries. The Bureaus activities include PGR exploration, collection, exchange, characterization, evaluation, conservation and documentation. It also has the responsibility to carry out quarantine of all imported PGR including transgenics meant for research purposes. The multifarious activities are carried out from ICAR-NBPGR headquarters and its 10 regional stations located in different agro-climatic zones of India. It has linkages with international organizations of the Consultative Group on International Agricultural Research (CGIAR) and national crop-based institutes to accomplish its mandated activities. NBPGR collects and acquires germplasm from various sources, conserves it in the Genebank, characterizes and evaluates it for different traits and provides ready material for breeders to develop varieties for farmers. ICAR-NBPGR encompasses the National Genebank Network and at present, the National Genebank conserves more than 0.40 million accessions. NBPGR works in service-mode for effective utilization of PGR in crop improvement programmes which depends mainly on its systematic characterization and evaluation, and identification of potentially useful germplasm. NBPGR is responsible for identifying trait-specific pre-adapted climate resilient genotypes, promising material with disease resistance and quality traits which the breeders use for various crop improvement programmes. The system has contributed immensely towards safeguarding the indigenous and introducing useful exotic PGR for enhancing the agricultural production. Presently, our focus is on characterization of ex situ conserved germplasm and detailed evaluation of prioritized crops for enhanced utilization; assessment of impact of on-farm conservation practices on genetic diversity; genome-wide association mapping for identification of novel genes and alleles for enhanced utilization of PGR; identification and deployment of germplasm/landraces using climate analog data; validation of trait-specific introduced germplasm for enhanced utilization

    Influence of organic nutrient sources and moisture management on productivity, biofortification and soil health in pearl millet (Pennisetum glaucum) + clusterbean (Cyamopsis tetragonaloba) intercropping system of semi-arid India

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    A field experimentation was carried out at New Delhi, India for three years (2010-12) under rainfed semi-arid conditions to assess the effect of three organic nutrient sources and two moisture management practices on productivity, biofortification and soil health under pearl millet [Pennisetum glaucum (L.) R. Br. emend Stuntz] + clusterbean [Cyamopsis tetragonaloba (L.) Taub] intercropping system (PCIS). In current study, the pearl millet grain yield under sole pearl millet was at par with PCIS while its stover yield reduced by 5%. Under PCIS, inclusion of clusterbean led to significant reduction in clusterbean yield compared to its sole stand, however, PCIS system productivity was more over their sole crop stands, indicating that additive series of PCIS may bring more net economic gains over their sole stands in semi-arid ecology of India. The coarse cereal-legume interactions under PCIS have also led to improved protein content in pearl millet (11.2%) over its sole stand (10.7%). Zinc (Zn) and iron (Fe) deficiency is a common feature in semi-arid India and the crops grown as well. Study revealed that Zn and Fe content in pearl millet were increased by 6.5 and 1.6%, respectively, by the inclusion of clusterbean in PCIS. Plant growth, yield attributes and yield of pearl millet and clusterbean crops showed an improvement under flat sowing + organic mulching (FS+OM) over ridge and furrow sowing (RFS) but the differences were non-significant. Among organic nutrient sources, leaf compost (LC) @ 10 t/ha and FYM @ 10 t/ha produced significantly more system productivity in terms of pearl millet-equivalent-yield (PEY) than 100% RDF and control. Protein content both in pearl millet and clusterbean, and Zn and Fe biofortification in pearl millet grains was higher under FYM treated plots closely followed by LC, and leaf + cowdung mixture compost. Application of organics especially FYM @ 10 t/ha also resulted in improved soil health in terms of bulk density, soil organic carbon and NPK status after three years experimentation

    jefA (Rv2459), a drug efflux gene in Mycobacterium tuberculosis confers resistance to isoniazid & ethambutol

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    Background & objectives: Drug efflux pumps have been contributing factor(s) in the development of multidrug resistance in various clinically relevant bacteria. During efflux pump gene expression studies on mycobacteria, we have found a previously uncharacterized open reading frame (ORF) Rv2459 to be overexpressed in drug stressed conditions. The objective of the present study was to investigate the role of this ORF as a drug efflux pump, which might add new information in our understanding about the alternative mechanisms of drug resistance in mycobacteria. Methods: The open reading frame Rv2459 of Mycobacterium tuberculosis encoding a probable drug efflux protein has been cloned using pSD5 E.coli-Mycobacterium shuttle vector and overexpressed in M. tuberculosis H37Rv. This ORF was named as jefA. Overexpression of this gene in clones has been verified by real-time reverse transcription PCR. Minimum inhibitory concentrations (MICs) of recombinant as well as non-recombinant clones were determined by resazurin microtitre assay plate method (REMA) with and without efflux pump inhibitors carbonyl cyanide m-chlorophenylhydrazone (CCCP) and verapamil. Results: In recombinant strains of M. tuberculosis, the overexpression of this gene led to an increase in MIC of anti-tubercular drugs isoniazid and ethambutol when tested by REMA. In the presence of CCCP and verapamil, the recombinant strains showed decrease in MIC for these drugs. Bioinformatic analysis has shown a close relation of JefA protein with drug efflux pumps of other clinically relevant bacteria. In homology derived structure prepared from nearest available model, it was observed that amino acids forming TMH 1, 8 and 11 participated in ethambutol specificity and those forming TMH 2, 7 and 10 participated in isoniazid specificity in JefA. Interpretation & conclusion: The increased transcription of jefA leads to increased resistance to ethambutol and isoniazid in M. tuberculosis via efflux pump like mechanism and contributes in the development of resistance to these drugs. JefA amino acid sequence is well conserved among clinically important bacterial genera, which further provides evidence of being a potent drug efflux pump. The involvement in drug resistance and very little homology with any of the human proteins makes JefA important to be included in the list of potential drug targets
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