47 research outputs found
An Efficient Codebook Initialization Approach for LBG Algorithm
In VQ based image compression technique has three major steps namely (i)
Codebook Design, (ii) VQ Encoding Process and (iii) VQ Decoding Process. The
performance of VQ based image compression technique depends upon the
constructed codebook. A widely used technique for VQ codebook design is the
Linde-Buzo-Gray (LBG) algorithm. However the performance of the standard LBG
algorithm is highly dependent on the choice of the initial codebook. In this
paper, we have proposed a simple and very effective approach for codebook
initialization for LBG algorithm. The simulation results show that the proposed
scheme is computationally efficient and gives expected performance as compared
to the standard LBG algorithm
Characterization of the Occult Hepatitis B Virus Variants Circulating among the Blood Donors from Eastern India
A previous study from West Bengal documented very high rate of occult HBV infection (OBI) among the HBsAg negative blood donors. This study was aimed to characterize the OBI strains circulating among the blood donors and to estimate the risk associated with the prevailing viral variants/mutants. Blood samples from 2195 voluntary blood donors were included in the study. HBsAg, HBeAg, anti-HBc, and anti-HBs statuses of the samples were done by ELISA based detection. PCR amplification and sequencing were done to determine HBV genotypes, basal core promoter (BCP), and precore (Pre-C) mutations. Among the study samples, 268 were anti-HBc positive/HBsAg negative, among which 65 (24.25%) were HBV DNA positive. Phylogenetic analysis revealed the presence of HBV/D (87.23%), HBV/A (8.51%), and HBV/C (4.26%) (P<0.0001).
HBV/D3 (65.85%) was the significantly prevalent subgenotype over HBV/D2 (26.83%) and HBV/D1 (7.31%) (P=0.0003). Considerable prevalence of differential BCP (1752C, 1753C, 1762T/1764A, 1753C+1762T/1764A, 1773C, and 1814C) and reverse transcriptase (rt) gene (rtI91L, rtL93P, rtS106C, rtR110G, rtN118T, rtS119T, rtY126H, rtG127W/R, rtC136R, and rtY158H) mutations was identified. Association of specific HBV subgenotypes with OBI was interesting and needs further study. Clinically relevant mutations were prevalent among the OBI strains which are of serious concern
Characterization of the Occult Hepatitis B Virus Variants Circulating among the Blood Donors from Eastern India
A previous study from West Bengal documented very high rate of occult HBV infection (OBI) among the HBsAg negative blood donors. This study was aimed to characterize the OBI strains circulating among the blood donors and to estimate the risk associated with the prevailing viral variants/mutants. Blood samples from 2195 voluntary blood donors were included in the study. HBsAg, HBeAg, anti-HBc, and anti-HBs statuses of the samples were done by ELISA based detection. PCR amplification and sequencing were done to determine HBV genotypes, basal core promoter (BCP), and precore (Pre-C) mutations. Among the study samples, 268 were anti-HBc positive/HBsAg negative, among which 65 (24.25%) were HBV DNA positive. Phylogenetic analysis revealed the presence of HBV/D (87.23%), HBV/A (8.51%), and HBV/C (4.26%) ( < 0.0001). HBV/D3 (65.85%) was the significantly prevalent subgenotype over HBV/D2 (26.83%) and HBV/D1 (7.31%) ( = 0.0003). Considerable prevalence of differential BCP (1752C, 1753C, 1762T/1764A, 1753C+1762T/1764A, 1773C, and 1814C) and reverse transcriptase (rt) gene (rtI91L, rtL93P, rtS106C, rtR110G, rtN118T, rtS119T, rtY126H, rtG127W/R, rtC136R, and rtY158H) mutations was identified. Association of specific HBV subgenotypes with OBI was interesting and needs further study. Clinically relevant mutations were prevalent among the OBI strains which are of serious concern
An Eight-year Study Report on Arsenic Contamination in Groundwater and Health Effects in Eruani Village, Bangladesh and an Approach for Its Mitigation
Based on several surveys during 1997-2005 and visits of a medical team
to Eruani village, Laksham upazila, Comilla district, Bangladesh, the
arsenic contamination situation and consequent clinical manifestations
of arsenicosis among the villagers, including dermatology, neuropathy,
and obstetric outcome, are reported here. Analysis of biological
samples from patients and non-patients showed high body burden of
arsenic. Even after eight years of known exposure, village children
were still drinking arsenic-contaminated water, and many of them had
arsenical skin lesions. There were social problems due to the symptoms
of arsenicosis. The last survey established that there is a lack of
proper awareness among villagers about different aspects of arsenic
toxicity. The viability of different options of safe water, such as
dugwells, deep tubewells, rainwater harvesting, and surface water with
watershed management in the village, was studied. Finally, based on 19
years of field experience, it was felt that, for any successful
mitigation programme, emphasis should be given to creating awareness
among villagers about the arsenic problem, role of arsenic-free water,
better nutrition from local fruits and vegetables, and, above all,
active participation of women along with others in the struggle against
the arsenic menace
Data from: An RGB colour image steganography scheme using overlapping block-based pixel-value differencing
This paper presents a steganographic scheme based on the RGB colour cover image. The secret message bits are embedded into each colour pixel sequentially by the pixel-value differencing (PVD) technique. PVD basically works on two consecutive non-overlapping components; as a result, the straightforward conventional PVD technique is not applicable to embed the secret message bits into a colour pixel, since a colour pixel consists of three colour components, i.e. red, green and blue. Hence, in the proposed scheme, initially the three colour components are represented into two overlapping blocks like the combination of red and green colour components, while another one is the combination of green and blue colour components, respectively. Later, the PVD technique is employed on each block independently to embed the secret data. The two overlapping blocks are readjusted to attain the modified three colour components. The notion of overlapping blocks has improved the embedding capacity of the cover image. The scheme has been tested on a set of colour images and satisfactory results have been achieved in terms of embedding capacity and upholding the acceptable visual quality of the stego-image
Stochastic dilation of a quantum dynamical semigroup on a separable unital C<SUP>∗</SUP> algebra
Given a uniformly continuous quantum dynamical semigroup on a separable unital C<SUP>∗</SUP> algebra, we construct a canonical Evans-Hudson (E-H) dilation. Such a result was already proved by Goswami and Sinha ([GS]) in the von-Neumann algebra set-up, which has been extended to the C<SUP>∗</SUP> algebraic framework in the present article. The authors make use of the coordinate-free calculus and results of [GS], but the proof of the existence of structute maps differs form that of [GS]
Zn Doping Induced Band Gap Widening of Ag2O Nanoparticles
The present investigation widens the
narrow bandgap of Ag2O to make it a semiconductor with more
attractive properties. A typical hydrothermal synthesis procedure was used to prepare
Zn doped Ag2O nanoparticles. The X-ray diffraction analysis of the
prepared powder samples showed that the lattice parameters of Ag2O
increase with doping, indicating the occupation
of interstitial positions by the dopant atoms. Density functional theory
calculations also demonstrated the expansion of the Ag2O crystal
lattice with the dopant at an interstitial location. The bandgap of the Ag2O
increases to 1.65 eV for 5-mole percent doping. The doped Ag2O
nanoparticles photocatalytically degrade methyl orange under aerobic visible
light conditions. It appears that the rise in the percentage of higher valence Zn
doping converts the originally p-type to an n-type semiconductor.</p