RSS Based Energy Efficient Scheme for the Reduction of Overhearing and Rebroadcast for MANET

AbstractIn MANET, reducing the amount of overhearing and rebroadcast based on Received Signal Strength (RSS) value can reduce the energy consumption. A cross layer framework is designed by combining the physical, MAC and network layer. In order to reduce the energy consumption, 802.11 PSM is integrated with DSR. Overhearing in DSR will improve the routing efficiency by expending some amount of energy. The main causes for energy consumption are unconditional overhearing and unnecessary rebroadcast of RREQ to the nodes which are having less Received Signal Strength (RSS). Here, RSS is used to predict the mobility of nodes. The less value of RSS indicates that the nodes are far away from the sender and this may lead to many path breakages. Probability of overhearing reduction (POR) is determined in order to limit the amount of hearing for the unicast packets. The proposed mechanism R-ROR avoids unnecessary overhearing and rebroadcast using cross layer design aiming to achieve energy consumption. Rebroadcast based on the RSS can reduce the number of path breakages, energy consumption and overhead. Simulation results are compared for Packet Delivery Ratio (PDR), energy consumption and delay. The analysis shows that R-ROR is energy efficient compared to 802.11, 802.11PSM, ODPM and RandomCast

NMR Relaxation Studies of Solvent D2O in Solutions of Monosubstituted Ammonium Compounds

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Characterization of a Toxigenic Vibrio cholerae O139 Strain Belonging to a New Ribotype and Isolated from a Diarrheal Patient

We characterized a Vibrio cholerae O139 strain isolated from a diarrheal patient admitted to Taluk Hospital, Cherthala, Alleppey, Kerala, India, on 9 June 2000. The V. cholerae O139 strain possesses the core of the CTX genetic element, colonization toxin-coregulated pilus, the adherence outer membrane protein, and the central regulatory protein encoded by toxR and produces cholera toxin (200 pg/ml). We provide molecular evidence showing that toxigenic V. cholerae O139 strain ALO95 belongs to a distinct genotype characterized by a unique ribotype designated B-VII and has a unique enterobacterial repetitive intergenic consensus sequence PCR fingerprint profile designated E-V

Molecular Characterization of Vibrio cholerae O139 Bengal Isolated from Water and the Aquatic Plant Eichhornia crassipes in the River Ganga, Varanasi, India

A collection of ten strains of Vibrio cholerae O139, comprising six isolates from Eichhornia crassipes, two from water of the River Ganga, and one each from a well and a hand pump, were characterized. All the strains carried the CTX genetic element (ctxA, zot, and ace) except for the st gene and carried structural and regulatory genes for toxin-coregulated pilus (tcpA, tcpI, and toxR), adherence factor (ompU), and accessory colonization factor (acfB); all produced cholera toxin (CT). These strains were resistant to trimethoprim, sulfamethoxazole, streptomycin, and to the vibriostatic agent pteridine. Results obtained by ribotyping and enterobacterial repetitive intergenic consensus sequence-PCR fingerprint analysis indicate that multiple clones of toxigenic-pathogenic V. cholerae O139 were present in the aquatic environment

Does Water Hyacinth on East African Lakes Promote Cholera Outbreaks?

Cholera outbreaks continue to occur regularly in Africa. Cholera has been associated with proximity to lakes in East Africa, and Vibrio cholerae has been found experimentally to concentrate on the floating aquatic plant, water hyacinth, which is periodically widespread in East African lakes since the late 1980s. From 1994 to 2008, Nyanza Province, which is the Kenyan province bordering Lake Victoria, accounted for a larger proportion of cholera cases than expected by its population size (38.7% of cholera cases versus 15.3% of national population). Yearly water-hyacinth coverage on the Kenyan section of Lake Victoria was positively associated with the number of cholera cases reported in Nyanza Province (r = 0.83; P = 0.0010). Water hyacinth on freshwater lakes might play a role in initiating cholera outbreaks and causing sporadic disease in East Africa