oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 556 matches for " Malay Kanti Sikdar "
All listed articles are free for downloading (OA Articles)
Page 1 /556
Display every page Item
A Different Approach for Big Bang Singularity  [PDF]
Malay Kanti Sikdar
Natural Science (NS) , 2018, DOI: 10.4236/ns.2018.104016
Abstract: With the discovery of Hubble Red Shift in the cosmological Universe, the question of Big Bang explosion has become inevitable and to explain this point of singularity thereon. Dissolution and manifestation of the universe happen to occur periodically. In this paper,analysis has been undertaken on the basis of scientific development on well accepted cosmological model, different scientific concepts and on one Vedic/Tantric scriptural remark. According to Vedic/Tantric scriptural remark, at the time of dissolution of the universe it remains in the form of gram. Different scientific tools like Electron Microscopy, X-rays powder diffraction method. Raman & UV spectroscopy have been applied in analyzing the two parts of gram and finally to find out what do they correspond to cosmological analysis of Big Bang singularity. Main mechanisms in action in dissolution and manifestation have also been pointed out.
MINIMIZATION OF MOBILITY MANAGEMENT COST IN LEO SATELLITE USING TRANSLATION OF COORDINATES
Suman Kumar Sikdar,Pijush Kanti Kumar,Debabrata Sarddar
International Journal of Advances in Engineering and Technology , 2013,
Abstract: Though Low Earth Orbit (LEO) satellites have some distinct characteristics such as low propagation delay, low power requirements and more efficient spectrum allocation due to frequency reuse between satellite and spot beams but the higher relative speed than terrestrial mobile networks but it decreases the quality of service as a result of a huge number of handovers. To overcome this problem a number of handover management schemes have been proposed out of which Mobile IP (MIP) is the standard one. But its mobility management cost is too high. Here we have proposed a low cost Coordinates based paging mobility management method (CBPMM) using translation of Coordinates and Paging for LEO satellite networks, which we can find the destination of the mobile node using GPS and translation of coordinates to decrease paging cost in loose location management. Through mathematical analysis simulation results shows that this method is better than the standard mobility management methods.
Magnitude distribution of earthquakes: Two fractal contact area distribution
Srutarshi Pradhan,Bikas K. Chakrabarti,Purussatam Ray,Malay Kanti Dey
Physics , 2003, DOI: 10.1238/Physica.Topical.106a00077
Abstract: The `plate tectonics' is an observed fact and most models of earthquake incorporate that through the frictional dynamics (stick-slip) of two surfaces where one surface moves over the other. These models are more or less successful to reproduce the well known Gutenberg-Richter type power law in the (released) energy distribution of earthquakes. During sticking period, the elastic energy gets stored at the contact area of the surfaces and is released when a slip occurs. Therefore, the extent of the contact area between two surfaces plays an important role in the earthquake dynamics and the power law in energy distribution might imply a similar law for the contact area distribution. Since, fractured surfaces are fractals and tectonic plate- earth's crust interface can be considered to have fractal nature, we study here the contact area distribution between two fractal surfaces. We consider the overlap set of two self-similar fractals, characterised by the same fractal dimensions, and look for their distribution. We have studied numerically the specific cases of both regular and random Cantor sets in one dimension and gaskets and percolation fractals in two dimension. We find that in all the cases the distributions show an universal finite size scaling behavior. The contact area distributions have got a power law decay for both regular and random Cantor sets and also for gaskets. However, for percolation clusters the distribution shows Gaussian variation.
Nutritional status among the Mising tribal children of Northeast India with respect to their arm fat area and arm muscle area
Mithun Sikdar
Human Biology Review , 2012,
Abstract: The study highlights the nutritional status of two thousand nine hundred and sixty five (2965) numbers of Mising (a scheduled tribe) children of Upper Assam with the help of two derived nutritional indices i.e. Arm Fat Area (AFA) and Arm Muscle Area (AMA). The mean values and their descriptive statistics of AFA as well as AMA are presented for each group of children starting from 6 to 20 years of age. A sexual variation has been found in terms of the mean values of both the indices and is more marked in the early childhood and late adolescent period. With respect to the United States standard the Arm Fat Area indicates that Mising girls suffer relatively more than the Mising boys. On the other hand with respect to Arm Muscle Area Mising boys are found to be more sufferer than the girls. The Mising boys shows higher mean values for AMA than those of the girls whereas an opposite trend of sexual variation is found with respect to AFA. The results indicate that the boys tend to accumulate more muscle and girls more fat in their growth period. With the present study it can be said that to delineate the nutritional status of a particular community several parameters should be taken into consideration at a time to come to a final conclusion.
Induction of Phase II Enzymes Glutathione-S-Transferase and NADPH: Quinone Oxydoreductase 1 with Novel Sulforaphane Derivatives in Human Keratinocytes: Evaluation of the Intracellular GSH Level  [PDF]
Sohely Sikdar, Benjamin Lallemand, Jacques Dubois
Pharmacology & Pharmacy (PP) , 2014, DOI: 10.4236/pp.2014.510105
Abstract: Phase II enzymes including NADPH: Quinone Oxydoreductase 1 (NQO1) and Glutathione-S-Transferase (GST) represents a major and natural cellular protection system against deleterious environmental factors which cause skin damages. Sulforaphane is one of the most popular isothiocyanates found in cruciferous vegetables and known for its cytoprotective effects by inducing Phase II enzymes. Five novel sulforaphane derivatives were synthetized and tested for their activity on NQO1 and GST induction as well as for their effect on total GSH intracellular level using colorimetric assays on human keratinocytes cell line (HaCat). As sulforaphane and the synthetized components showed variable toxicity after their evaluation by means of in vitro cytotoxicity (MTT test), cells were treated at a concentration of 5 μM during 48 hours. The results showed that the addition products of sulforaphane decreased cytotoxity but none of those derivatives had a better effect than referenced sulforaphane on Phase II enzymes. It seems that the isothiacyanate function remains important for the sulforaphane activity.
Effect of -Lipoic Acid on Proteasomal Induction: Protection against Oxidative Damage in Human Skin Fibroblasts Cell Line NHDF  [PDF]
Sohely Sikdar, Maria Papadopoulou, Jacques Dubois
Pharmacology & Pharmacy (PP) , 2017, DOI: 10.4236/pp.2017.89022
Abstract: As human skin is daily exposed to oxidative stress causing various unesthetical abnormalities, the road to effective anti-aging substances is being widely investigated. 20S proteasome is a key pathway in the breakdown of oxidized proteins. But its activity declines dramatically in aging cells. Nrf2 inducers -lipoic acid (LA) and sulforaphane (SFN) have been described in the dietary industries for their antioxidant effects on various cell lines. However, since little is yet known about LA’s capacity to protect skin cells from premature and extrinsic aging; our aim was to demonstrate the beneficial effect of LA on the cellular detoxification systems. On this purpose, we evaluated its effects against injuries induced by H2O2 in NHDF and its likely positive effect on the chymotrypsin-like (CT-like) activity of 20S proteasome, using SFN as a reference. The cellular content in proteins was measured, as well as the production of Reactive Oxygen Species (ROS). Also, the induction of the proteasomal protein expression was investigated. The results show that after 48 h treatment, LA significantly decreased the percentage of ROS positive cells. Also, LA decreased the level of H2O2-induced carbonylated proteins and increased the proteasomal activity. Furthermore, LA upregulated the expression of the 20S proteasome ß-subunit responsible for the CT-like activity (PSMB5). Overall, both molecules enhanced cell proliferation over 8 days. So, our investigation found evidence of the higher capacity of LA to induce 20S proteasome activity with less toxicity in human fibroblasts compared to reference molecule SFN. These results tend to demonstrate that the induction of the proteasomal activity might be a part of the antioxidant potential of LA. To our knowledge, this is the first study to elucidate the capacity of LA to activate detoxification systems in human cell lines through the induction of 20S proteasome.
A Comparison of VaR Estimation Procedures for Leptokurtic Equity Index Returns  [PDF]
Malay Bhattacharyya, Siddarth Madhav R
Journal of Mathematical Finance (JMF) , 2012, DOI: 10.4236/jmf.2012.21002
Abstract: The paper presents and tests Dynamic Value at Risk (VaR) estimation procedures for equity index returns. Volatility clustering and leptokurtosis are well-documented characteristics of such time series. An ARMA (1, 1)-GARCH (1, 1) approach models the inherent autocorrelation and dynamic volatility. Fattailed behavior is modeled in two ways. In the first approach, the ARMA-GARCH process is run assuming alternatively that the standardized residuals are distributed with Pearson Type IV, Johnson SU, Manly’s exponential transformation, normal and t-distributions. In the second approach, the ARMA-GARCH process is run with the pseudonormal assumption, the parameters calculated with the pseudo maximum likelihood procedure, and the standardized residuals are later alternatively modeled with Mixture of Normal distributions, Extreme Value Theory and other power transformations such as John-Draper, Bickel-Doksum, Manly, Yeo-Johnson and certain combinations of the above. The first approach yields five models, and the second ap-proach yields nine. These are tested with six equity index return time series using rolling windows. These models are compared by computing the 99%, 97.5% and 95% VaR violations and contrasting them with the expected number of violations.
A Note on Crank-Nicolson Scheme for Burgers’ Equation  [PDF]
Kanti Pandey, Lajja Verma
Applied Mathematics (AM) , 2011, DOI: 10.4236/am.2011.27118
Abstract: In this work we generate the numerical solutions of the Burgers’ equation by applying the Crank-Nicolson method directly to the Burgers’ equation, i.e., we do not use Hopf-Cole transformation to reduce Burgers’ equation into the linear heat equation. Absolute error of the present method is compared to the absolute error of the two existing methods for two test problems. The method is also analyzed for a third test problem, nu-merical solutions as well as exact solutions for different values of viscosity are calculated and we find that the numerical solutions are very close to exact solution.
Charged oscillator in a heat bath in the presence of a magnetic field & third law of thermodynamics
Malay Bandyopadhyay
Physics , 2008,
Abstract: The quantum thermodynamic behaviour of a charged oscillator in the presence of a magnetic field and coupled to a heat bath through different coupling schemes is obtained analytically. It is shown that finite dissipation substitutes the zero-coupling result of exponential decay of entropy by a power law behaviour at low temperature. For the coordinate-coordinates coupling scheme the low temperature explicit results for the case of Ohmic, exponentially correlated and more generalized heat bath models are derived. In all the above mentioned cases free energy and entropy vanish linearly with temperature ($T$) as $T\to 0$ in conformity with Nernst's theorem. It is seen that coordinate (velocity)-velocities (coordinates) coupling is much more beneficial than the coordinate-coordinates coupling to ensure third law of thermodynamics. The case of radiation heat bath shows $T^3$ decay behaviour for entropy as $T\to 0$. It is observed that at low temperature free energy and entropy decay faster for the velocity-velocities scheme than any other coupling schemes. This implies velocity-velocities coupling scheme is the most advantageous coupling scheme in restoring the third law of thermodynamics. It is shown that the low temperature thermodynamic functions are independent of magnetic field for all the above mentioned cases except the without dissipation case.
Nucleation of superconductivity under rapid cycling of electric field
Malay Bandyopadhyay
Physics , 2009,
Abstract: The effect of an externally applied high frequency oscillating electric field on the critical nucleation field of superconductivity in the bulk as well as at the surface of a superconductor is investigated in details in this work. Starting from the linearized time dependent Ginzburg-Landau (TDLG) theory and using the variational principle we have shown the analogy between a quantum harmonic oscillator with that of the nucleation of superconductivity in bulk and a quantum double oscillator with that of the nucleation at the surface of a finite sample. The effective Hamiltonian approach of Cook {\it et al} \cite{cook} is employed to incorporate the effect of an externally applied highly oscillating electric field. The critical nucleation field ratio is also calculated from the ground state energy method. The results obtained from these two approximated theories agree very well with the exact results for the case of undriven system which establishes the validity of these two approximated theories. It is observed that the highly oscillating electric field actually increases the bulk critical nucleation field ($H_{c_2}$) as well as the surface critical nucleation field ($H_{c_3}$) of superconductivity as compared to the case of absence of electric field ($\varepsilon_0=0$). But the externally applied rapidly oscillating electric field accentuates the surface critical nucleation field more than the bulk critical nucleation field i.e. the increase of $H_{c_3}$ is 1.6592 times larger than that of $H_{c_2}$.
Page 1 /556
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.