Relationship Between Quantum Walk and Relativistic Quantum Mechanics

Quantum walk models have been used as an algorithmic tool for quantum computation and to describe various physical processes. This paper revisits the relationship between relativistic quantum mechanics and the quantum walks. We show the similarities of the mathematical structure of the decoupled and coupled form of the discrete-time quantum walk to that of the Klein-Gordon and Dirac equations, respectively. In the latter case, the coin emerges as an analog of the spinor degree of freedom. Discrete-time quantum walk as a coupled form of the continuous-time quantum walk is also shown by transforming the decoupled form of the discrete-time quantum walk to the Schrodinger form. By showing the coin to be a means to make the walk reversible, and that the Dirac-like structure is a consequence of the coin use, our work suggests that the relativistic causal structure is a consequence of conservation of information. However, decoherence (modelled by projective measurements on position space) generates entropy that increases with time, making the walk irreversible and thereby producing an arrow of time. Lieb-Robinson bound is used to highlight the causal structure of the quantum walk to put in perspective the relativistic structure of quantum walk, maximum speed of the walk propagation and the earlier findings related to the finite spread of the walk probability distribution. We also present a two-dimensional quantum walk model on a two state system to which the study can be extended.Comment: 12 pages and 1 figure, Published versio

Microstructure and Mechanical Properties of Aluminum Cast Alloy A356 reinforced with Dual-Size B4C Particles

The paper details the studies carried out on a dual-size particulate composite prepared by stir casting using A 356 aluminum alloy and B4C powders. Three composite compositions, viz., A356 plus 2% B4C (44µm size and 105µm size in 1:1 ratio), 4% B4C (3:1 ratio), and 6% B4C (1:3 ratio) were cast in finger molds, from which test specimens were prepared for hardness and tensile tests as well as for metallography. Vickers hardness tests, tensile tests and microstructure analysis using an optical microscope were conducted. The results obtained indicated that the B4C particles were evenly distributed in the alloy matrix. EDS also revealed the presence of B4C in all the three composites.  In general, the hardness and tensile strengths increased with increase in concentration B4C powders. While the increase in hardness was increases less than 15%, there was significant increase (more than 35 %) in tensile strength. However, the ductility represented by % elongation, which was already very low in A 356 cast alloy (24.2%,), further decreased in composites. Tensile fractography results shows inter crystalline fracture where the breakage in the B4C particle instead of deboning were observed

Accessibility vs. Usability – Where is the Dividing Line?

Web accessibility for people with disabilities may be looked upon as the overcoming of barriers that make it difficult for them to use Web resources. Web accessibility for people with disabilities may be looked upon as the overcoming of barriers that prevent them from using these resources. Web accessibility can be improved through the use of assistive technologies in some cases by enabling access through alternative or enhanced modes. Web usability has been popular for longer than Web accessibility and theory, techniques, and guidelines relating to Web accessibility are more recent than those of Web usability. Accessibility could thus be considered as having a narrower scope than usability. Accessibility of Web resources by people with disabilities, which involves both access and use, is best supported by a combination of a set of accessibility guidelines and a set of usability guidelines

In vitro pharmacological potential of Epiprinus mallotiformis – An endemic species of Western Ghats

Epiprinus mallotiformis is an endemic species of Western Ghats, traditionally known to cure dysentery, digestive problems, ulcers, gonorrhoea and also as a good antimicrobial and diuretic agent. The present investigation was done to evaluate the in vitro pharmacological activities and preliminary screening for phytochemicals in leaf, stem and bark extracts. The study revealed an optimum antioxidant, anti-inflammatory and antimicrobial activities and the presence of phenolics, flavonoids and saponins in the plant extracts. The ethyl acetate fraction of leaf samples exhibited a very significant antibacterial activity against S. aureus with a minimum bactericidal concentration of 8 mg/mL which might be due to the presence of high saponin content (9 %) in the leaves. The investigation also suggests the possible use of E. mallotiformis as an antioxidant, anti-inflammatory and antibacterial agent

PHYTOCHEMICAL EVALUATION AND IN VITRO ANTIMICROBIAL AND ANTIOXIDANT STUDIES OF LEAF AND STEM BARK EXTRACTS OF POLYALTHIA FRAGRANS (DALZ.) BEDD.–AN ENDEMIC SPECIES OF WESTERN GHATS

Objective: Phytochemical constituents of various solvent extracts of leaf and stem bark of Polyalthia fragrans (Dalz.) Bedd were screened. Antimicrobial and antioxidant activities of the extracts were evaluated.Methods: Crude extracts of methanol, ethyl acetate, chloroform and aqueous of leaf and stem bark were evaluated for antimicrobial activity by disc diffusion method and antioxidant activity by DPPH (diphenyl-2-picrylhydrazyl) radical scavenging and reducing power assay. Quantitative analysis of total phenolics was done by the Folin-Ciocalteau method and total flavonoids by aluminum chloride method.Results: The study revealed the presence of several physiologically active phytochemicals such as alkaloids, phenols, flavonoids and tannins. The highest antibacterial activity of methanol extract of the leaf was observed against Bacillus subtilis with 14.33±0.57 mm inhibition zone and water extract of stem bark against Proteus vulgaris with 17.67±1.52 mm inhibition zone among other extracts. The lowest activity of leaf methanol and leaf water extract was observed against Bacillus subtilis. The IC50 values of 58.18±2.04 µg/ml, 116.58±2.43 µg/ml, 134.78±3.64 µg/ml and 387.28±2.9 µg/ml for DPPH activity were observed in methanol stem bark, ethyl acetate stem bark, methanol leaf and ethyl acetate leaf extracts respectively. The reducing power of extracts was very potent which increased with increasing concentrations of the sample.Conclusion: The results indicate that phytochemicals like alkaloids, phenols, flavonoids and tannins may be responsible for the antimicrobial and antioxidant properties. The results suggest that P. fragrans can be further researched to be used as a natural source of a potent drug by mankind

Acute anti-inflammatory activity of ethanolic extract of leaves of Leucas indica by carrageenan induced paw oedema in wistar albino rats

Background: Inflammation is basically a defense phenomenon but can lead to serious pathological conditions. It is treated by various agents with good to moderate success because of both considerable toxicity and side effects. There are various mediators to cause an inflammatory reaction that can contribute to the associated symptoms and tissue injury. Even though non steroidal anti-inflammatory drugs are the most commonly prescribed drugs in the world, their use as anti-inflammatory agents continues to be principally limited by their undesired side effects. Hence, the traditional medical practitioners and scientists are turning towards Indian System of Medicine (ISM).Methods: Dried powdered leaves of Leucas indica were subjected to solvent extraction by using 90 % ethanol. Based on acute oral toxicity study according to Organization for Economic Cooperation and Development (OECD) guidelines No. 423, three doses of the test drug 75, 150 & 300mg/kg were selected and subjected to preclinical anti-inflammatory screening by carrageenin induced paw oedema in Wistar Albino rats.Results : Oral administration of Ethanolic Extract Of Leaves Of Leucas Indica (EELLI) at doses of 150 mg/kg and 300mg/kg showed significant anti-inflammatory activity 52.58% (p<0.01) and 36.87% (p<0.05) respectively compared to control. Conclusion: Even though oral administration of EELLI has shown significant anti-inflammatory activity, further studies are required to evaluate its comprehensive analysis including quantitative / semi quantitative analysis, characterize its chemical structure and assess its pharmacotherapeutic activities with exact mechanism of action as an anti-inflammatory agent