Secure group communication

With the advent of digital technologies and widening Internet bandwidth in recent years there has been a marked rise in new multimedia services, including teleconferencing, pay-per-view TV, interactive simulations, software updates and real-time delivery of stock market information. Multicast data distribution has been used in controlled environments to deliver such services. However, the lack of secure, accountable multicast data distribution has prevented its use in general Internet environments. Proposals for multicast security solutions so far are complex and often require trust in intermediate components or are inefficient. A secure multicast protocol suite must provide for data confidentiality, for multicast packet source authentication and for the representation of multicast security policies. In this thesis we present a robust, simple and efficient multicast key management protocol based on proxy encryption, a multicast data source authentication mechanism based on symmetric message authentication codes and a simple multicast policy representation scheme based on XML. The solutions are analyzed and compared to previously published schemes. The results show that the proposed schemes are efficient and scalable when compared to existing schemes

RP relocation in protocol independent multicast-sparse mode

Protocol Independent Multicast - Sparse Mode is the most widely used multicast routing architecture. It builds a shared distribution tree centered at a Rendezvous Point and then builds source-specific trees for those sources whose data traffic warrants it. Current implementations of the protocol decide on the locations of the Rendezvous Point administratively, which leads to congestion and delays. An attractive solution would be dynamic relocation of the Rendezvous Point depending on the members of the multicast group. In this thesis we present a Rendezvous Point calculation and relocation mechanism for Protocol Independent Multicast - Sparse Mode

Collective modes of gluons in an anisotropic thermo-magnetic medium

We study the collective modes of gluon in an anisotropic thermal medium in presence of a constant background magnetic field using the hard-thermal loop (HTL) perturbation theory. The momentum space anisotropy of the medium has been incorporated through the generalized $`$Romatschke-Strickland' form of the distribution function, whereas, the magnetic modification arising from the quark loop contribution has been taken into account in the lowest Landau level approximation. We consider two special cases: (i) a spheroidal anisotropy with the anisotropy vector orthogonal to the external magnetic field and (ii) an ellipsoidal anisotropy with two mutually orthogonal vectors describing aniostropies along and orthogonal to the field direction. The general structure of the polarization tensor in both cases are equivalent and consists of six independent basis tensors. We find that the introduction of momentum anisotropy ingrains azimuthal angular dependence in the thermo-magnetic collective modes. Our study suggests that the presence of a strong background magnetic field can significantly reduce the growth rate of the unstable modes which may have important implications in the equilibration of magnetized quark-gluon plasma.Comment: 15 pages, 6 figure

Applications and Constraints of Plant Beneficial Microorganisms in Agriculture

At present time, chemical fertilizers are more in practice for crop production, which failed to upkeep soil and environment quality and affected the sustainability of the agricultural production system. Conversely, biofertilizers are ecosystem friendly, one of the best modern tools for agriculture, and are used to improve soil fertility and quality. Biofertilizers have now emerged as a highly potent alternative to inorganic fertilizers and offer an ecologically sound and economically attractive route for augmenting nutrient supply and increasing crop production. These include live cells of diverse genera of microorganisms and have the potential to fix atmospheric nitrogen and solubilize and mobilize plant nutrients from insoluble form through microbiological process. It has also the potential to diminish the gap between nutrient supply through fertilizers and nutrient removal by crops. Hence, biofertilizers can be a feasible option to the farmers to increase crop productivity and should find greater acceptance from the extension workers and commercial biofertilizer manufacturers

Deltamethrin induced alterations of hematological and biochemical parameters in fingerlings of Catla catla (Ham.) and their amelioration by dietary supplement of vitamin C

The present study was carried out to investigate the sub-lethal toxicity of technical grade deltamethrin (a synthetic pyrethroid) of concentration 1.61 μg/L (1/3rd of 96 h LC50) on hematological and biochemical parameters of catla (Catla catla) fingerlings and its amelioration through dietary vitamin C. The deltamethrin exposed fishes were fed with different levels of supplemented vitamin C such as 50, 250, 500 and 1000 mg/kg diet to see its ameliorating effect by assaying hematological parameters viz. total erythrocyte count (TEC), total leukocyte count (TLC), hemoglobin content (Hb), total serum protein, albumin, globulin, albumin–globulin ratio and biochemical parameters such as lactate dehydrogenase (LDH), acetylcholine esterase (AChE), alanine amino transferase (ALT), aspartate amino transferase (AST), total adenosine triphosphatase (ATPase), magnesium adenosine triphosphatase (Mg2+-ATPase) and sodium potassium adenosine triphosphatase (Na+, K+-ATPase) activities. The finding of this study showed that deltamethrin had negative effect on the hematological and biochemical parameters of Catla catla. The experimental group, which was exposed to deltamethrin and fed with normal diet showed significantly lower values (P ⩽ 0.05) of all parameters studied except ALT activity. This might be due to possible disruption of hematopoiesis and proteosynthesis. However, the fish fed with varied concentration of vitamin C in diets neutralized the toxic effect of deltamethrin, as evidenced by significantly lowered hematological and biochemical response. Vitamin C @ 1000 mg/kg diet was the most effective in amelioration of harmful effect of deltamethrin on hematological and biochemical parameters of catla fingerlings. The result suggests that vitamin C can be effectively used to neutralize the toxic effect of deltamethrin on catla

Effect of dietary supplementation of Bacillus subtilis on haematological and immunological parameters of Catla catla (Hamilton)

Effect of dietary supplementation of a Gram-positive, aerobic, probiotic bacterium Bacillus subtilis on the immunohaematological indices during pre- and post-challenge in Indian major carp, catla (Catla catla), was studied. The B. subtilis was administered orally at four different doses 1.0 × 106 (T1), 1.0 × 107 (T2), 1.0 × 108 (T3), and 1.0 × 109 (T4) cfu g−1 feed to C. catla for 90 days. The positive control (Cp) and negative control (Cn) were fed with feed without B. subtilis for the same period. On the 60th day, blood and serum were sampled to determine various haematological and serum parameters. Fish were challenged intraperitoneally with Aeromonas hydrophila after 60 days in all the treatment groups and Cp, while the Cn was challenged with phosphate-buffered saline (PBS, pH 7.2) only. Dietary supplementation of B. subtilis leads to the rise of various immunological and haematological parameters in catla during the pre- and post-challenge. During pre-challenge, the highest TEC (1.30 ± 0.02 × 106 cells mm−3), haemoglobin (7.43 ± 0.25 g %), total serum protein (3.89 ± 0.08 g dL−1), and serum lysozyme activity (8.39 ± 0.01 µg ml−1) were recorded in fishes fed feed containing B. subtilis at 1 × 109 cfu/g feed (T4). The highest survival percentage (86.33 %) was also observed in T4 group. The significantly increased survival percentage (P < 0.05) of B. subtilis-treated groups in comparison with control group (Cp) suggests that dietary supplementation of this probiotic bacterium can protect catla from A. hydrophila infection by enhancing innate immunity

Fusion cross sections for 6,7Li + 24Mg reactions at energies below and above the barrier

Measurement of fusion cross sections for the 6,7Li + 24Mg reactions by the characteristic gamma-ray method has been done at energies from below to well above the respective Coulomb barriers. The fusion cross sections obtained from these gamma-ray cross sections for the two systems are found to agree well with the total reaction cross sections at low energies. The decrease of fusion cross sections with increase of energy is consistent with the fact that other channels, in particular breakup open up with increase of bombarding energy. This shows that there is neither inhibition nor enhancement of fusion cross sections for these systems at above or below the barrier. The critical angular momenta (lcr) deduced from the fusion cross sections are found to have an energy dependence similar to other Li - induced reactions.Comment: 1 .pdf fil