Holographic Probes of Anti-de Sitter Spacetimes

We describe probes of anti-de Sitter spacetimes in terms of conformal field theories on the AdS boundary. Our basic tool is a formula that relates bulk and boundary states -- classical bulk field configurations are dual to expectation values of operators on the boundary. At the quantum level we relate the operator expansions of bulk and boundary fields. Using our methods, we discuss the CFT description of local bulk probes including normalizable wavepackets, fundamental and D-strings, and D-instantons. Radial motions of probes in the bulk spacetime are related to motions in scale on the boundary, demonstrating a scale-radius duality. We discuss the implications of these results for the holographic description of black hole horizons in the boundary field theory.Comment: 28 pages, LaTex. References adde

A New Cryptographic Strategy for Digital Images

In this paper, a new image block cipher encryption strategy for gray scale images using a different set of secret key and sizes is proposed. Initially, the swapping and dispersion is done without keys and in second stage the image is mixed with the chirikov map involving first secret key.  'N' rounds are taken to complete this process. The blended image is divided into blocks of block size 8X8.These blocks are also swapped to achieve good confusion. For making the encryption scheme more sturdy in each block the transmutation of pixels is done with the modified logistic map having three more secret keys.  The proposed scheme is simple, rapid and sensitive to the secret key. Due to the high order of substitution, common attacks such as linear and differential cryptanalysis are unattainable. The experimental results show that the proposed encryption technique is effective and has high security features.DOI:http://dx.doi.org/10.11591/ijece.v4i3.632

Enhanced Transmission and Receiver Diversity in Orthogonal Frequency Division Multiplex Systems using Blind Channel Estimation

This paper deals with the blind channel estimation technique in OFDM system with receiver diversity to analyze the bit error rate with respect to the number of symbols. The paper clearly brings out the advantage that is being offered by the use of Blind channel estimation technique in terms of SNR requirements. Also a comparative study has been made for the analysis of BER variation with the amount i.e. number of symbols being transmitted. The work also explores the possibility of obtaining an optimum value of number of receivers that may lead to desired BER for threshold value of SNR in an OFDM system

Restructuring in Telecommunications and its Market Impacts: An Event-Study Analysis

The aim of the study is to present a detailed assessment of the major strategic changes in the telecommunications industry and their impact on market returns. Using a global sample of major telecom companies, significant events related to restructuring were identified and then assessed in terms of their favorable or unfavorable impacts. Based on the methodology of event-study analysis with GARCH specification, the impact of events was tested after incorporating dummy variables of different lengths (7, 15 and 20). Simultaneously, subsequent to a regression, Cumulative Abnormal Returns (CAR) were calculated within a variable event window of 7, 15 and 20 Days. Market returns were studied starting from 1996 until 2008. The results show interesting patterns in terms of how the market views restructuring in the business model of telecom companies, organizational structure, alliances and mergers, and technological platform changes. Countries differ significantly in how they view telecoms restructuring and what changes are considered beneficial by investor and which ones are not

Data Flow in Wireless Sensor Network Protocol Stack by using Bellman-Ford Routing Algorithm

Wireless sensor network consists various sensor nodes that are used to monitor any target area like forest fire detection by our army person and monitoring any industrial activity by industry manager. Wireless sensor networks have been deployed in several cities to monitor the concentration of dangerous gases for citizens. In wireless sensor network when sensor nodes communicate from each other then routing protocol are used for communication between protocol layers. Wireless sensor network protocol stack consist five layers such as Application layer, Transport layer, Network layer, MAC Layer, Physical layer. In this paper we study and analysis Bellman-Ford routing algorithm and check the flow of data between these protocol layers. For simulation purpose we are using Qualnet 5.0.2 simulator tool

Biotransformation of Chrysin to Baicalein: Selective C6-Hydroxylation of 5,7-Dihydroxyflavone Using Whole Yeast Cells Stably Expressing Human CYP1A1 Enzyme

© 2017 American Chemical Society. Naturally occurring polyphenolic compounds are of medicinal importance because of their unique antioxidant, anticancer, and chemopreventive properties. Baicalein, a naturally occurring polyhydroxy flavonoid possessing a diverse range of pharmacological activities, has been used in traditional medicines for treatment of various ailments. Apart from its isolation from natural sources, its synthesis has been reported via multistep chemical approaches. Here, we report a preparative-scale biotransformation, using whole yeast cells stably expressing human cytochrome P450 1A1 (CYP1A1) enzyme that allows regioselective C6-hydroxylation of 5,7-dihydroxyflavone (chrysin) to form 5,6,7-trihydroxyflavone (baicalein). Molecular modeling reveals why chrysin undergoes such specific hydroxylation mediated by CYP1A1. More than 92% reaction completion was obtained using a shake-flask based process that mimics fed-batch fermentation. Such highly efficient selective hydroxylation, using recombinant yeast cells, has not been reported earlier. Similar CYP-expressing yeast cell based systems are likely to have wider applications in the syntheses of medicinally important polyphenolic compounds

Phytochemical investigation and anti-Inflammatory activity of Coccinia indica wight and arn. (Cucurbitaceae) fruits

The present work was to study the anti-inflammatory activity of Coccinia indica Wight and Arn fruits belonging to family Cucurbitaceae. The fruit powder of C. indica was subjected to successive extraction with petroleum ether, chloroform, ethanol and water in a Soxhlet extractor. The ethanol extract after preliminary phytochemical investigation shown the presence of glycosides, triterpenoids, flavonoids, tannins and phenolic compounds. The anti-inflammatory activity was studied using carrageenan-induced rat paw oedema and cotton pellet granuloma at three different doses (100, 200 and 400 mg/kg b.w. p.o.) of each extract. The ethanol extract of C. indica fruits exhibited significant anti-inflammatory activity at the dose of 200 mg/kg and 400 mg/kg in both models when compared with control group. Indomethacin (10 mg/kg b.w. p.o) also showed significant anti-inflammatory activity in both models.Colegio de Farmacéuticos de la Provincia de Buenos Aire