T-duality invariant effective actions at orders α′,α′2 \alpha', \alpha'^2

We use compatibility of the $D$-dimensional effective actions for diagonal metric and for dilaton with the T-duality when theory is compactified on a circle, to find the the $D$-dimensional couplings of curvatures and dilaton as well as the higher derivative corrections to the $(D-1)$-dimensional Buscher rules at orders $\alpha'$ and $\alpha'^2$. We observe that the T-duality constraint on the effective actions fixes the covariant effective actions at each order of $\alpha'$ up to field redefinitions and up to an overall factor. Inspired by these results, we speculate that the $D$-dimensional effective actions at any order of $\alpha'$ must be consistent with the standard Buscher rules provided that one uses covariant field redefinitions in the corresponding reduced $(D-1)$-dimensional effective actions. This constraint may be used to find effective actions at all higher orders of $\alpha'$.Comment: 24 pages, latex file, no figure; v2: major modifications; v3: the version appears in JHE

Policy Space and Voting Coalitions in Congress: The Bearing of Policy on Politics, 1930-1954

The question of how the substance of politics helps shape legislative coalitions and bases of support has been displaced from the center of studies of Congress since the publication of pioneering work in the 1960s and early 1970s. Seeking to revive this research program, the authors apply an original coding scheme in tandem with a factor analytic analysis of voting and policy space to the period spanning the last years of the Hoover presidency to the start of Eisenhower's. Investigating legislator parameters—the dimensions of voting space—and roll call parameters—the dimensions of policy space—the paper confirms the strong independent impact of the substance of policy on the political decisions of legislators and reveals an issue-specific concatenation of party and region that altered over the course of the period

Dependence of band structure and carrier concentration of metallic (13, 13) and semiconducting (13, 0) single wall carbon nanotube on temperature

The electronic band structure, density of states (DOS) and carrier concentration of a (13,13) metallic and a (13,0) semiconducting Single Wall Carbon Nanotube (SWCNT) have been estimated and simulated by using the Fermi-Dirac distribution function. The energy dispersion E(k) relation for metallic SWCNT near the minimum energy is linear and the Fermi level was independent of temperature (T). On the other hand for semiconducting SWCNT the E(k) relation is parabolic. The normalized Fermi-Energy (EF – EC) in the nondegenerate regime is a weak (logarithmic) function of carrier concentration and varies linearly with T. In the degenerate condition, the Fermi level was independent of T and was a strong function of carrier concentration

High Power Two- Stage Class-AB/J Power Amplifier with High Gain and Efficiency

This paper presents a hybrid Broadband power amplifier which provides high drain efficiency. AB and J, Two Classes of power amplifier are described using GaN HEMT with matching networks together with input and output compact elements. Using Load Pull method, the best input and output network in the central frequency of 3GHz for output power of 40dBm, 10dB high gain and high efficiency of 80%, has been designed. After describing the design of each of the amplifiers and comparing their performance, the proposed circuit, two-class AB/J are discussed to be the target of the circuit design, reducing the input power to achieve high efficiency output power and gain. Input and output matching proposed circuit elements in terms of theory and simulation are compared, and the results of both investigations were similar. Also, the fundamental harmonic and the second harmonic in the 0.5GHz bandwidth have the desirable amplitude of the output signal

High Power Two- Stage Class-AB/J Power Amplifier with High Gain and Efficiency

This paper presents a hybrid Broadband power amplifier which provides high drain efficiency. AB and J, Two Classes of power amplifier are described using GaN HEMT with matching networks together with input and output compact elements. Using Load Pull method, the best input and output network in the central frequency of 3GHz for output power of 40dBm, 10dB high gain and high efficiency of 80%, has been designed. After describing the design of each of the amplifiers and comparing their performance, the proposed circuit, two-class AB/J are discussed to be the target of the circuit design, reducing the input power to achieve high efficiency output power and gain. Input and output matching proposed circuit elements in terms of theory and simulation are compared, and the results of both investigations were similar. Also, the fundamental harmonic and the second harmonic in the 0.5GHz bandwidth have the desirable amplitude of the output signal

Numerical solutions for a class stochastic partial differential equations

The aim of this manuscript is to introduce and analyze a stochastic finite difference  scheme for Ito stochastic partial differential equations. We also discuss the consistency, stability, and convergence for the stochastic finite difference scheme. The numerical simulations obtained from the proposed  stochastic finite difference scheme show the efficiency of the suggested  stochastic finite difference scheme

Gravity/CFT correspondence for three dimensional Einstein gravity with a conformal scalar field

We study the three dimensional Einstein gravity conformally coupled to a scalar field. Solutions of this theory are geometries with vanishing scalar curvature. We consider solutions with a constant scalar field which corresponds to an infinite Newton's constant. There is a class of solutions with possible curvature singularities which asymptotic symmetries are given by two copies of the Virasoro algebra. We argue that the central charge of the corresponding CFT is infinite. Furthermore, we construct a family of Schwarzschild solutions which can be conformally mapped to the Martinez-Zanelli solution of Einstein's equations with a negative cosmological constant coupled to conformal scalar field.Comment: 27 pages, to appear in Nucl. Phys.