Hop aware scheduling algorithm for TCP performance enhancement in multi hop relay wimax

Mobile Multi-hop Relay (MMR) WiMAX networks allow the number of hops between the user and the MMR-BS to be more than two hops when the non transparent relay station is used. Transmission Control Protocol (TCP) protocol is optimized to be used in wired networks where the main cause of loss is the congestion. TCP throughput is highly affected by packet losses or timeout occurrences because of its congestion control mechanism. Upon the occurrence of timeout, TCP decreases the transmission window which results in throughput degradation, even if such losses are not due to congestion. This paper presents link layer scheduling algorithm to enhance the TCP in IEEE 802.16j MMR WiMAX networks. The aim is to reduce the Retransmission Timeout (RTO) occurrences and enhance the throughput. The results showed that the hop aware scheduling algorithm gives higher throughput, and less timeout occurrence for different BER values

Generalized observers and velocity measurements in General Relativity

To resolve some unphysical interpretations related to velocity measurements by static observers, we discuss the use of generalized observer sets, give a prescription for defining the speed of test particles relative to those observers and show that, for any locally inertial frame, the speed of a freely falling material particle is always less than the speed of light at the Schwarzschild black hole surface.Comment: 20 pages, 1 figure, submitted to General Relativity and Gravitatio

Postharvest control of Rhizopus stolonifer on blackberry (Rubus fruticosus) by blackberry native crop bacteria

The potential of four native bacterial strains of blackberries cv. Brazos (Rubus fruticosus): Bacillus subtilis (BSS), Bacillus subtilis (BSL), Bacillus licheniformis (BLI) and Leifsonia aquatica (LAQ), was evaluated for the postharvest control of soft rot caused by Rhizopus stolonifer in blackberry fruits. The fruits were treated with cell suspensions (CS) and cell-free supernatants (CFE) from each bacterial strain and were infected with two strains of R. stolonifer (RSA and RSC). The severity and inhibition percentage of the disease were determined. Additionally, the inhibition by siderophores and the inhibition percentage of R. stolonifer spore germination were analyzed as possible control mechanisms. The CS of BSS inhibited RSA by 45.8%, followed by CFE of LAQ which controlled the same strain by 39.7%. The CS of BLI inhibited RSC by 37.7%, whereas the CFE of BSS and LAQ controlled it by 47.7 and 41.8%, respectively. All bacterial strains inhibited RSA and RSC by siderophores production (38.7 to 48.6 %) and the inhibition of spore germination of RSC was higher than 93% after 48 h. This work is one of the first to report R. stolonifer control by native bacteria CS and CFE, particularly LAQ in postharvested blackberry fruits. These results show the combination of mechanisms used by bacteria to control both R. stolonifer strains.The potential of four native bacterial strains of blackberries cv. Brazos (Rubus fruticosus): Bacillus subtilis (BSS), Bacillus subtilis (BSL), Bacillus licheniformis (BLI) and Leifsonia aquatica (LAQ), was evaluated for the postharvest control of soft rot caused by Rhizopus stolonifer in blackberry fruits. The fruits were treated with cell suspensions (CS) and cell-free supernatants (CFE) from each bacterial strain and were infected with two strains of R. stolonifer (RSA and RSC). The severity and inhibition percentage of the disease were determined. Additionally, the inhibition by siderophores and the inhibition percentage of R. stolonifer spore germination were analyzed as possible control mechanisms. The CS of BSS inhibited RSA by 45.8%, followed by CFE of LAQ which controlled the same strain by 39.7%. The CS of BLI inhibited RSC by 37.7%, whereas the CFE of BSS and LAQ controlled it by 47.7 and 41.8%, respectively. All bacterial strains inhibited RSA and RSC by siderophores production (38.7 to 48.6 %) and the inhibition of spore germination of RSC was higher than 93% after 48 h. This work is one of the first to report R. stolonifer control by native bacteria CS and CFE, particularly LAQ in postharvested blackberry fruits. These results show the combination of mechanisms used by bacteria to control both R. stolonifer strains

Two-Dimensional Electronic Spectroscopy of Chlorophyll a: Solvent Dependent Spectral Evolution

The interaction of the monomeric chlorophyll Q-band electronic transition with solvents of differing physical-chemical properties is investigated through two-dimensional electronic spectroscopy (2DES). Chlorophyll constitutes the key chromophore molecule in light harvesting complexes. It is well-known that the surrounding protein in the light harvesting complex fine-tunes chlorophyll electronic transitions to optimize energy transfer. Therefore, an understanding of the influence of the environment on the monomeric chlorophyll electronic transitions is important. The Q-band 2DES is inhomogeneous at early times, particularly in hydrogen bonding polar solvents, but also in nonpolar solvents like cyclohexane. Interestingly this inhomogeneity persists for long times, even up to the nanosecond time scale in some solvents. The reshaping of the 2DES occurs over multiple time scales and was assigned mainly to spectral diffusion. At early times the reshaping is Gaussian-like, hinting at a strong solvent reorganization effect. The temporal evolution of the 2DES response was analyzed in terms of a Brownian oscillator model. The spectral densities underpinning the Brownian oscillator fitting were recovered for the different solvents. The absorption spectra and Stokes shift were also properly described by this model. The extent and nature of inhomogeneous broadening was a strong function of solvent, being larger in H-bonding and viscous media and smaller in nonpolar solvents. The fastest spectral reshaping components were assigned to solvent dynamics, modified by interactions with the solute

Full characterization of vibrational coherence in a porphyrin chromophore by two-dimensional electronic spectroscopy

In this work we present experimental and calculated two-dimensional electronic spectra for a 5,15-bisalkynyl porphyrin chromophore. The lowest energy electronic Qy transition couples mainly to a single 380 cm–1 vibrational mode. The two-dimensional electronic spectra reveal diagonal and cross peaks which oscillate as a function of population time. We analyze both the amplitude and phase distribution of this main vibronic transition as a function of excitation and detection frequencies. Even though Feynman diagrams provide a good indication of where the amplitude of the oscillating components are located in the excitation-detection plane, other factors also affect this distribution. Specifically, the oscillation corresponding to each Feynman diagram is expected to have a phase that is a function of excitation and detection frequencies. Therefore, the overall phase of the experimentally observed oscillation will reflect this phase dependence. Another consequence is that the overall oscillation amplitude can show interference patterns resulting from overlapping contributions from neighboring Feynman diagrams. These observations are consistently reproduced through simulations based on third order perturbation theory coupled to a spectral density described by a Brownian oscillator model

Registration of ICGV-SM 85048 Peanut Germplasm

ICGV-SM 85048 (Reg. no. GP-90, PI 598134), an improved Spanish peanut (Arachis hypogaea L. subsp.fastigiata var. vitlgaris) germplasm, was developed at the SADC/ICRISAT (Southern African Development Community/International Crops Research Institute for the Semi-Arid Tropics) Groundnut Project in Malawi. It was first tested at the Mauritius Sugar Industry Research Institute (MSIRI), Mauritius, in 1988. After evaluations in on-station and on-farm trials, it was released in 1992 as 'Stella' in Mauritius (8). It is suitable for cultivation both in sugarcane (Sacchanim officinarum L.) interrows and in pure stand

Registration of groundnut cultivar Sylvia (ICGV 93207)

ICGV 93207 as Sylvia is a high-yielding improved spanish groundnut genotype developed at ICRISAT, Patancheru, India, and released by the Mauritius Sugar Industry Research Institute, in 1998 for commercial plantation in pure stand and in sugarcane interrows in Mauritius. It was derived from a cross between 2 advanced breeding lines, ICGV 86594 and ICGV 86672. Sylvia significantly outyielded the popular control cultivar Cabri by 38.8% with more stable yields than the control. It is adapted to all soils and regions in Mauritius where groundnut is grown. It is resistant to rust (caused by Puccinia arachidis). The yield performance and other characteristics of ICGV 93207 are given

Registration of Groundnut Cultivar Venus (ICGV 87853)

Released in 1998, the virginia bunch new variety Venus was developed by bulk selection from the cross of Kadiri 3 (ICG 799) with a stable, interspecific derivative CS-9. Venus has a decumbent habit, and matures in 120-125 days during the rainy season and in 135-140 days during the post-rainy season. It has two-seeded pods which have a small beak, a slight constriction and moderate reticulation. Mean pod size is 34 mm × 10 mm. Shelling percentage averages 68% while 100-seed weight ranges from 32 to 52 g depending on season and location. Seeds are tan coloured. Pod yield in trials conducted at Patancheru during kharif 1990 and 1991 gave mean yields of 1.58 t/ha outyielding ICGS 76 by 43.7% and Kadiri 3 by 64.6%. Venus is resistant to rust (Puccinia arachidis) and is moderately tolerant of late leaf spot (Mycosphaerella berkeleyi)

Vaccines against toxoplasma gondii : challenges and opportunities

Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge

Water Dynamics at Protein Interfaces: Ultrafast Optical Kerr Effect Study

The behavior of water molecules surrounding a protein can have an important bearing on its structure and function. Consequently, a great deal of attention has been focused on changes in the relaxation dynamics of water when it is located at the protein surface. Here we use the ultrafast optical Kerr effect to study the H-bond structure and dynamics of aqueous solutions of proteins. Measurements are made for three proteins as a function of concentration. We find that the water dynamics in the first solvation layer of the proteins are slowed by up to a factor of 8 in comparison to those in bulk water. The most marked slowdown was observed for the most hydrophilic protein studied, bovine serum albumin, whereas the most hydrophobic protein, trypsin, had a slightly smaller effect. The terahertz Raman spectra of these protein solutions resemble those of pure water up to 5 wt % of protein, above which a new feature appears at 80 cm–1, which is assigned to a bending of the protein amide chain