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Kolkata, India

Chakraborty T.,Bethune College | Giri B.C.,Jadavpur University
Operational Research | Year: 2014

The paper studies the joint effect of shift, inspections, imperfect preventive maintenance (PM) and imperfect rework of defective items on optimal decisions for a deteriorating production system. At the time of inspection during a production run, either PM or restoration is done depending on the state of the production process. There is a probability that PM action may shift the process from 'in-control' state to 'out-of-control' state. During the 'out-of-control' phase, the system produces some defective items which go for rework at the end of the production run. A portion of the reworked items may also fail repairing. The model is formulated for the case of general inspections and analyzed under two well known inspection policies-periodic inspection policy and constant cumulative hazard inspection policy. For numerical examples, a comparison of the outcomes of the model with and without reworks under these two inspection policies is made. It is observed that the periodic inspection policy performs better than the constant cumulative hazard policy. © 2013 Springer-Verlag Berlin Heidelberg. Source

Ghosh S.,Bethune College | Ghosh B.,RKMVC College | Jha S.,University of Calcutta
Plant Tissue Culture and Biotechnology | Year: 2015

Elicitation strategies were studied for yield enhancement of colchicine, produced by root cultures of Gloriosa superba. Adventitious root cultures were established and grown in media containing 3 mg/l NAA and 1 mg/l BA. Root cultures showed variations in biomass as well as colchicine production in the presence of different exogenous carbohydrates and amino acid. Among the different sources of carbohydrates used ‐ fructose, sucrose and dextrose gave a substantially higher biomass yield than the control. Maximum biomass was obtained in the presence of fructose. Root cultures growing in mannitol supplemented medium resulted in maximum accumulation of colchicine (0.32%). Among the amino acids, serine and phenylalanine significantly enhanced colchicine accumulation in root cultures. 0.02 mM glutamine supplemented media showed maximum (ten‐fold) increase of root biomass. © 2015, Bangladesh Association for Plant Tissue. All rights reserved. Source

Sinha A.,Jadavpur University | Roychoudhury R.,Bethune College | Roychoudhury R.,Advanced Center for Nonlinear and Complex Phenomena
Journal of Mathematical Physics | Year: 2013

We present an analytical study for the scattering amplitudes (Reflection |R| and Transmission |T|), of the periodic PT symmetric optical potential V(x) = W0(cos2x + i vo sin 2x)confined within the region 0 ≤ x ≤ L, embedded in a homogeneous medium having uniform potential W0. The confining length L is considered to be some integral multiple of the period π. We give some new and interesting results. Scattering is observed to be normal (|T|2 ≤ 1, |R|2 ≤ 1) for V0 ≤ 0.5, when the above potential can be mapped to a Hermitian potential by a similarity transformation. Beyond this point (V0 > 0.5) scattering is found to be anomalous (|T|2, |R|2 not necessarily ≤1). Additionally, in this parameter regime of V0, one observes infinite number of spectral singularities ESS at different values of V0. Furthermore, for L = 2nπ, the transition point V0 = 0.5 shows unidirectional invisibility with zero reflection when the beam is incident from the absorptive side (Im[V(x)] < 0) but with finite reflection when the beam is incident from the emissive side (Im[V(x)] > 0), transmission being identically unity in both cases. Finally, the scattering coefficients |R|2 and |T|2 always obey the generalized unitarity relation: ||T|2- 1| = √|RR|2|RL|2, where subscripts R and L stand for right and left incidence, respectively. © 2013 AIP Publishing LLC. Source

Sanyal S.,Bethune College | Banerjee S.,University of Calcutta
Archives of Polish Fisheries | Year: 2013

In this study, the thermotolerent fecal coliform (Th FC) bacterial population (n = 81) in a waste-fed aquaculture system was examined for multiple antibiotic resistance and the possession of transferable drug resistance factors (R factors). Multiple antibiotic resistant (MAR) coliforms were found to be common in the sewage-fed pond environment, with 83% of the screened MAR isolates harboring plasmids of > 10 kilo base pair (kb). The transfer of resistance was confirmed by mating experiments in 92% of plasmid-positive MAR coliforms with a nalidixic acid (NA) resistant strain, Escherichia coli ATCC (American Tissue Type Cell Culture) 14948 recipient in the presence of DNase (Deoxyribonuclease). Antibiotic resistance profiles of some mated progenies (70.83%) indicated that transfer was unidirectional. DNase-treated cell-free supernatants did not transform, which excluded transduction. A DNase-resistant conjugation-like mechanism probably plays a major role in the transfer of resistance factors. Physical evidence of transmissible resistance factors in fish suggests a potential health risk to humans and animals, including farmed fish. ©Inland Fisheries Institute in Olsztyn. Source

Gupta B.,Bose Institute of India | Gupta B.,Presidency University of India | Gupta K.,Bose Institute of India | Gupta K.,Bethune College | Sengupta D.N.,Bose Institute of India
Acta Physiologiae Plantarum | Year: 2012

Plants respond to abiotic stresses such as salinity, extreme temperature and drought by the activation of complex intracellular signaling cascades that regulate acclimatory biochemical and physiological changes. Protein kinases are major signal transduction factors that play a central role in mediating acclimation to environmental changes in eukaryotic organisms. It is well known that changes in abiotic conditions such as the concentration of ions, temperature and humidity lead to modulation of polyamine contents in plants. However, little is known about the relevant part these polyamines play in abiotic stress responses. Here, we address a specific role of spermidine during high salt stress by studying its interaction with OSPDK, a sucrose nonfermenting 1-related protein kinase2 (SnRK2)-type serine/threonine protein kinase SAPK4 homolog in indica rice. In this report, we demonstrate that spermidine mediates in vitro phosphorylation of OSBZ8, a bZIP class of ABRE-binding transcription factor, by OSPDK. Our results give a first-hand indication of the pivotal role played by polyamines in abiotic stress cell signaling in plants. © 2012 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków. Source

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