The Plane-Wave/Super Yang-Mills Duality

We present a self-contained review of the Plane-wave/super-Yang-Mills duality, which states that strings on a plane-wave background are dual to a particular large R-charge sector of N=4, D=4 superconformal U(N) gauge theory. This duality is a specification of the usual AdS/CFT correspondence in the "Penrose limit''. The Penrose limit of AdS_5 S^5 leads to the maximally supersymmetric ten dimensional plane-wave (henceforth "the'' plane-wave) and corresponds to restricting to the large R-charge sector, the BMN sector, of the dual superconformal field theory. After assembling the necessary background knowledge, we state the duality and review some of its supporting evidence. We review the suggestion by 't Hooft that Yang-Mills theories with gauge groups of large rank might be dual to string theories and the realization of this conjecture in the form of the AdS/CFT duality. We discuss plane-waves as exact solutions of supergravity and their appearance as Penrose limits of other backgrounds, then present an overview of string theory on the plane-wave background, discussing the symmetries and spectrum. We then make precise the statement of the proposed duality, classify the BMN operators, and mention some extensions of the proposal. We move on to study the gauge theory side of the duality, studying both quantum and non-planar corrections to correlation functions of BMN operators, and their operator product expansion. The important issue of operator mixing and the resultant need for re-diagonalization is stressed. Finally, we study strings on the plane-wave via light-cone string field theory, and demonstrate agreement on the one-loop correction to the string mass spectrum and the corresponding quantity in the gauge theory. A new presentation of the relevant superalgebra is given.Comment: RevTeX 4 format; 91 pages; 7 figures. Prepared for Reviews of Modern Physics. Please send comments to darius, jabbari @ itp.stanford.edu. v3: Minor typos fixe

Noncommutativity in Space and Primordial Magnetic Field

In this paper we show that noncommutativity in spatial coordinates can generate magnetic field in the early Universe on a horizon scale. The strength of such a magnetic field depends on the number density of massive charged particles present at a given moment. This allows us to trace back the temperature dependence of the noncommutativity scale from the bounds on primordial magnetic field coming from nucleosynthesis.Comment: Revtex, 4 pages, v3: very minor changes, the version to appear in PR

Study on genetic variability in some agro-morphological traits of Brassica rapa L. (Brown sarson) germplasm characterized under rainfed conditions of Kashmir, India

36 Brassica rapa L. (Brown sarson) genotypes were characterized during two successive seasons of 2013/14 and 2014/15 along with two national checks (Puas Kalyani and GSL-2) and one local check variety (Shalimar-1) to assess the extent of variability and amount of variation in agro-morphological traits of plant height, number of primary branches/plant, days to 50% flowering, number of seeds/siliqua, seed yield/plant and 1000-seed weight. Important traits of plant height varied from 58.35 cm - 95.36 cm, seed yield/plant from 3.840 g - 18.470 g and 1000-seed weight from 2.746 g - 4.377 g. Analysis of variance revealed significant differences at 0.05 level of probability among different genotypes for these characters during a particular year while differences were non-significant in all the traits excepting days to 50% flowering when data of the two years was compared. Highest variability, phenotypic coefficient of variation (33.89%) and genotypic coefficient of variation (30.99%) were recorded for the trait seed yield/plant. High heritability coupled with high to moderate per cent genetic advance was recorded for seed yield/plant and 1000-seed weight indicating that these traits can be improved through simple selection. Moderate heritability with low genetic advance was observed in all other traits suggesting greater influence of environment. Promising donor genotypes for all these traits have been identified for possible utilization in breeding programmes in the region

Architecture and Implementation of a Trust Model for Pervasive Applications

Collaborative effort to share resources is a significant feature of pervasive computing environments. To achieve secure service discovery and sharing, and to distinguish between malevolent and benevolent entities, trust models must be defined. It is critical to estimate a device\u27s initial trust value because of the transient nature of pervasive smart space; however, most of the prior research work on trust models for pervasive applications used the notion of constant initial trust assignment. In this paper, we design and implement a trust model called DIRT. We categorize services in different security levels and depending on the service requester\u27s context information, we calculate the initial trust value. Our trust value is assigned for each device and for each service. Our overall trust estimation for a service depends on the recommendations of the neighbouring devices, inference from other service-trust values for that device, and direct trust experience. We provide an extensive survey of related work, and we demonstrate the distinguishing features of our proposed model with respect to the existing models. We implement a healthcare-monitoring application and a location-based service prototype over DIRT. We also provide a performance analysis of the model with respect to some of its important characteristics tested in various scenarios

Trajectory Tracking of a Four Degree of Freedom Robotic Manipulator

A robotic manipulator can be utilized for multiple applications. As there are some expensive and bulky robotic manipulators with multi-functionalities are available in the market but not affordable for many people, a low-cost robotic manipulator, Dobot Magician, available in the market is used in this research to add more features in it. The forward kinematics and inverse kinematics are analyzed in this research besides studying about PID and computed torque control approaches. In this research, alphabets and numbers are coded using an object-oriented programming language (C#) to make the learning of alphabet, numbers, words, and sentence writing more fun to the children. Moreover, it has been found that the same robot and the same operation can be implemented in other applications. A speech recognizer is implemented to control the robot to execute some activities of daily living tasks which make it more accessible to the elderly individuals and the people with disabilities

Coverage bias of Bangladesh television media: a portrayal of power and politics

After the fall of autocratic regime of military ruler in 1990, the political governments in Bangladesh has created platform of media expansion through ‘privatization policy’. The only state-run Bangladesh Television (BTV) was in operation till mid-1990s but the number of privately owned satellite channels has rose to a few dozens, at present. This growth is perceived abnormal in terms of role and professionalism of the channels to the society since their affiliation with the political parties is critically viewed for managing license. This study aims to explore the coverage bias of the TV channels through analyzing the contents of 130 reports selected purposively from three TV channels, both the state-run and corporate owned. It reveals that 51 reports (39%) concentrated on power, politics and elites; the highest thematic coverage by the selected channels. The ruling party got the highest coverage where the Prime Minister, Ministers, Members of the Parliament and the senior political leaders were projected with importance. The reports were mostly male dominated and urban focused. Thus, the television channels portrayed the powerful and influential classes neglecting the common people who represent an empire of the dominant classes in Bangladesh

Considerations in Designing Human-Computer Interfaces for Elderly People

As computing devices continue to become more heavily integrated into our lives, proper design of human-computer interfaces becomes a more important topic of discussion. Efficient and useful human-computer interfaces need to take into account the abilities of the humans who will be using such interfaces, and adapt to difficulties that different users may face – such as the difficulties that elderly users must deal with. Interfaces that allow for user-specific customization, while taking into account the multiple difficulties that older users might face, can assist the elderly in properly using these newer computing devices, and in doing so possibly achieving a better quality of life through the advanced technological support that these devices offer. In this paper, we explore common problems the elderly face when using computing devices and solutions developed for these problems. Difficulties ultimately fall into several categories: cognition, auditory, haptic, visual, and motor-based troubles. We also present an idea for a new adaptive operating system with advanced customizations that would simplify computing for older users