Parameter Estimation of a Noisy Real Sinusoid Using Quartic Polynomial Approach

An analytical polynomial expression, for accurate and computationally efficient frequency estimation of a single real sinusoid under Additive White Gaussian Noise (AWGN), is derived and proposed in this paper. The method, which can be easily adapted for real time frequency estimation, is based on transforming the frequency estimation problem as the solution of a fourth order (quartic) expressed as powers of a trigonometric function containing the unknown frequency. The coefficients of the quartic polynomial can be found using the complex magnitudes of three Discrete Fourier Transform (DFT) bins, centered at the maximum magnitude value of the DFT coefficients. Simulated results illustrate that, the performance of the proposed estimator has a mean squared-error (MSE) performance which is very close to the Cramer Rao Lower Bound (CRLB) for high signal-to-noise ratio (SNR) region, as well as close to previously published estimators in the low SNR region

Cholesterol metobolism of macrophages in relation to the presence of Mycobacterium leprae

Macrophages phagocytose Mycobacterium leprae and live bacilli inside such macrophages alter the lipid metabolism. There is increased accumulation of cholesterol ester in the bacteria infected cells. This increase appears to be due to the decreased level of esterase enzyme that could hydrolyse cholesterol esters. Associated with decreased level of this enzyme is the reduced amount of protein synthesis. Increased cholesterol ester may be responsible for conversion of macrophages into foamy cells in the presence of M. leprae

Antioxidant and antimitotic activities of sulfated polysaccharide from marine brown algae Padina tetrastromatica

Antioxidants play a central role in the prevention of carcinogenesis. The most natural compounds exhibit their protective effects by eliciting antioxidant potential. Sulfated polysaccharide was isolated from the brown algae Padina tetrastromatica, then purified and evaluated for its composition and in vitro antioxidant and antimitotic activities. Both ethanolic sulfated polysaccharide (ESPS) and ethanolic sulfated polysaccharide-column purified (ESPS-CP) exhibited considerable amount of carbohydrates (11.2% and 17.6%), sulfate (11.4% and 7.4%), fucose (5.5% and 15.7%), uronic acid (4.7% and 11.8%), xylose (0.5% and 0.03%) and sulfated polysaccharide (2.4% and 12.7%) content. The FTIR analysis and phytochemical screening also confirmed the presence of sulfated polysaccharides. In the in vitro antioxidant activity determination using DPPH (1-1-diphenyl 2-picryl hydrazyl) radical scavenging activity, hydroxyl radical scavenging activity, superoxide anion scavenging activity, hydrogen peroxide scavenging activity, total antioxidant activity and reducing power, ESPS showed more activity than ESPS-CP. In the case of nitric oxide radical scavenging, ESPS-CP was found to be more effective. At a concentration of 2mg/ml, both samples were potent antioxidants with significant IC50 values. The antimitotic studies such as mitotic index in onion root tips and sprouting assay in green gram seeds also proved that both the extracts are able to prevent mitosis. The extrapolation of these results can find opportunities in therapeutic regiments of cancer

Bifunctional eff ect of fucoidan from Padina tetrastromatica against human pathogenic microbes and free radicals

The antibacterial and antioxidant effect of fucoidan fractions isolated from brown algae Padina tetrastromatica was evaluated. Even though the polysaccharide was found to be a fucan, the composition of this polysaccharide is different from those reported, and the antibacterial and antioxidant effect has not been reported so far. Three fractions (F1, F2, and F3) were isolated by anion-exchange column chromatography. Chemical analysis suggested that the polysaccharide fractions contained a significant amount of sulfate and fucose, galactose xylose, andmannose as the major neutral sugars. Antibacterial activity was checked by disk diffusion method. Antioxidant activity was investigated by various in vitro systems, including 1,1-diphenyl-2-picrylhydrazyl radical scavenging,lipid peroxide inhibition, superoxide and hydroxyl radical scavenging activity, chelating ability and reducingpower. Antibacterial and antioxidant assays suggested that the polysaccharide fraction F3 possessed goodantibacterial activity and had stronger antioxidant properties than F1 and F2. Available data obtained by in vitromodels suggested that the correlation between the sulfate content and pharmacological effect was positive.Fucoidan from P. tetrastromatica have the potential to be developed as anantibacterial and antioxidant agent, butfurther in vivo research for their mode of action are still needed to shed light on the effects. Overall, the presentexperiments showed fucoidan from marine brown algae as a potential therapeutic agent

Tidal waves cause damages to coastal villages in Kerala

The article reports on the damages caused by giant tidal waves to coastal villages between Aarattupuzha (Alleppey District) in the south and Nattika (Trichur District) in the north for a distance of about 150 km along the Kerala coast. The giant tidal waves struck hard against the shore and rolled over into the low lying areas filling the sea water in the huts, wells, paddy fields etc. The damages were the minimum where ever the sea walls were present. But such calamities are unpredictable, hence the practical solution to such sudden natural calamities is to protect the coast line by constructing sea wall wherever the same is not present

Analysis of Pointing Error on Satellite Link using GNU Radio

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Expanded genetic screening in Caenorhabditis elegans identifies new regulators and an inhibitory role for NAD+ in axon regeneration.

The mechanisms underlying axon regeneration in mature neurons are relevant to the understanding of normal nervous system maintenance and for developing therapeutic strategies for injury. Here, we report novel pathways in axon regeneration, identified by extending our previous function-based screen using the C. elegans mechanosensory neuron axotomy model. We identify an unexpected role of the nicotinamide adenine dinucleotide (NAD+) synthesizing enzyme, NMAT-2/NMNAT, in axon regeneration. NMAT-2 inhibits axon regrowth via cell-autonomous and non-autonomous mechanisms. NMAT-2 enzymatic activity is required to repress regrowth. Further, we find differential requirements for proteins in membrane contact site, components and regulators of the extracellular matrix, membrane trafficking, microtubule and actin cytoskeleton, the conserved Kelch-domain protein IVNS-1, and the orphan transporter MFSD-6 in axon regrowth. Identification of these new pathways expands our understanding of the molecular basis of axonal injury response and regeneration

Status, prospects and management of small pelagic fisheries in India

The annual small pelagic fish production increased from 0.30 million mt during 1950-54 to 1.24 million mt during 1996 along the Indian coast. The 4 fold increase was possible due to several technological advancements. The potenrial yield from the pelagic resources of the EEZ is estimated to be 2.2 million mt. As there is no further scope for increasing the production from the inshore waters, there is need to bring the outer shelf and oceanic waters into increasing levels of exploitation