शिवमंगल सिंह 'सुमन' के काव्य का विचार-पक्ष

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Capacity of a POST Channel with and without Feedback

We consider finite state channels where the state of the channel is its previous output. We refer to these as POST (Previous Output is the STate) channels. We first focus on POST($\alpha$) channels. These channels have binary inputs and outputs, where the state determines if the channel behaves as a $Z$ or an $S$ channel, both with parameter $\alpha$. %with parameter $\alpha.$ We show that the non feedback capacity of the POST($\alpha$) channel equals its feedback capacity, despite the memory of the channel. The proof of this surprising result is based on showing that the induced output distribution, when maximizing the directed information in the presence of feedback, can also be achieved by an input distribution that does not utilize of the feedback. We show that this is a sufficient condition for the feedback capacity to equal the non feedback capacity for any finite state channel. We show that the result carries over from the POST($\alpha$) channel to a binary POST channel where the previous output determines whether the current channel will be binary with parameters $(a,b)$ or $(b,a)$. Finally, we show that, in general, feedback may increase the capacity of a POST channel

Effective Test Pattern Generation using LFSR for Memory Testing

Volume 2 Issue 3 (March 2014

Colossal electroresistance in ferromagnetic insulating state of single crystal Nd0.7_0.7Pb0.3_0.3MnO3_3

Colossal electroresistance (CER) has been observed in the ferromagnetic insulating (FMI) state of a manganite. Notably, the CER in the FMI state occurs in the absence of magnetoresistance (MR). Measurements of electroresistance (ER) and current induced resistivity switching have been performed in the ferromagnetic insulating state of a single crystal manganite of composition Nd$_0.7$Pb$_0.3$MnO$_3$ (NPMO30). The sample has a paramagnetic to ferromagnetic (Curie) transition temperature, Tc = 150 K and the ferromagnetic insulating state is realized for temperatures, T <~ 130 K. The colossal electroresistance, arising from a strongly nonlinear dependence of resistivity ($\rho$) on current density (j), attains a large value ($\approx 100$) in the ferromagnetic insulating state. The severity of this nonlinear behavior of resistivity at high current densities is progressively enhanced with decreasing temperature, resulting ultimately, in a regime of negative differential resistivity (NDR, d$\rho$/dj < 0) for temperatures <~ 25 K. Concomitant with the build-up of the ER however, is a collapse of the MR to a small value (< 20%) even in magnetic field, H = 7 T. This demonstrates that the mechanisms that give rise to ER and MR are effectively decoupled in the ferromagnetic insulating phase of manganites. We establish that, the behavior of ferromagnetic insulating phase is distinct from the ferromagnetic metallic (FMM) phase as well as the charge ordered insulating (COI) phase, which are the two commonly realized ground state phases of manganites.Comment: 24 pages (RevTeX4 preprint), 8 figures, submitted to PR

Antimutagenic Potential of Probiotic Lactobacillus sporogenes Using Ames assay

Objective: Probiotic are beneficial microbial nutrition supplements which have useful effects on human health by conserving of bowel microbial balance. There are many studies that have been recommended the use of probiotic products as cancer risk reducer. The aim of present study was to investigate antimutagenic potential of Probiotic Lactobacillus sporogenes against TA98 and TA100 strain of Salmonella typhimurium.Material and Methods: Ames test was used in the present investigation to evaluate antimutagenic activity in TA98 and TA100 strains of Salmonella typhimurium using direct acting mutagens (Sodium azide) and different concentration of Probiotic L.Sporogenes (25, 50, 100 and 500 μg/0.1 ml/plate).Results: Probiotic Lactobacillus sporogenes showed significant antimutagenicity against mutagen sodium azide in TA98 and TA100 tester strains whereas it showed antimutagenicity result in inhibition of 93-97% and 62-88% of his+ revertants induced by sodium azide in TA98 and TA100 strains respectively.Conclusion: The antimutagenicity of Probiotic Lactobacillus sporogenes the observed in the present study implies chemopreventive pharmacological importance of Probiotic Lactobacillus sporogenes and encourages its use as a biotherapeutic agent

Curcumin: A medicinal plant and its effects in medicine and dentistry

Since ancient time plants have been a major source of medicine. Curcumin (diferuloylmethane) is an orange-yellow component of turmeric (Curcuma longa), a spice often found in curry powder. Traditionally known for its anti-inflammatory effects, C. longa has a long history of the curative use in the Ayurvedic and Chinese systems of medicine. Curcumin, a polyphenolic constituent, is the active ingredient in dietary spice turmeric. While numerous pharmacological activities, including antioxidant and antimicrobial properties, anti-inflammatory properties have been attributed to curcumin, turmeric can also be used as a pit and fissure sealant, mouthwash, and subgingival irrigant in various preparations. In gel form, it is a component in local drugs delivery system. This review gives a bird’s eye view mainly on the biological activities of the miswak and plausible medicinal and dental application