3,885 research outputs found

    Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks

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    In this paper, we investigate the performance of a dual-hop block fading cognitive radio network with underlay spectrum sharing over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-mm fading channels. The primary network consists of a source and a destination. Depending on whether the secondary network which consists of two source nodes have a single relay for cooperation or multiple relays thereby employs opportunistic relay selection for cooperation and whether the two source nodes suffer from the primary users' (PU) interference, two cases are considered in this paper, which are referred to as Scenario (a) and Scenario (b), respectively. For the considered underlay spectrum sharing, the transmit power constraint of the proposed system is adjusted by interference limit on the primary network and the interference imposed by primary user (PU). The developed new analysis obtains new analytical results for the outage capacity (OC) and average symbol error probability (ASEP). In particular, for Scenario (a), tight lower bounds on the OC and ASEP of the secondary network are derived in closed-form. In addition, a closed from expression for the end-to-end OC of Scenario (a) is achieved. With regards to Scenario (b), a tight lower bound on the OC of the secondary network is derived in closed-form. All analytical results are corroborated using Monte Carlo simulation method

    Observation of SLE(κ,ρ)(\kappa,\rho) on the Critical Statistical Models

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    Schramm-Loewner Evolution (SLE) is a stochastic process that helps classify critical statistical models using one real parameter κ\kappa. Numerical study of SLE often involves curves that start and end on the real axis. To reduce numerical errors in studying the critical curves which start from the real axis and end on it, we have used hydrodynamically normalized SLE(κ,ρ\kappa,\rho) which is a stochastic differential equation that is hypothesized to govern such curves. In this paper we directly verify this hypothesis and numerically apply this formalism to the domain wall curves of the Abelian Sandpile Model (ASM) (κ=2\kappa=2) and critical percolation (κ=6\kappa=6). We observe that this method is more reliable for analyzing interface loops.Comment: 6 Pages, 8 Figure

    Primary Epstein-Barr virus infection in a 40-day-old infant

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    Most cases of primary Epstein-Barr virus (EBV) infection during infancy and early childhood are mild or subclinical; therefore, the diagnosis of an EBV infection is not performed easily in this age group. Infectious mononucleosis (IM) is rarely reported during infancy. We report a 40-day-old infant with cervical node enlargement, cough, and coryza symptoms who was finally identified as having a case of primary IM based on the patient's clinical features and serological tests. © 2013 - IOS Press and the authors. All rights reserved

    Five dimensional cosmological traversable wormhole

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    In this paper, a traversable wormhole in the Friedmann-Lema\^{\i}tre-Robertson-Walker (FLRW) model with one extra spacelike compact dimension is studied. We have chosen dynamical compactification as the evolution of the fifth dimension. In this respect, we study how the existence of the extra dimension, affect the behavior of the energy density, the shape function and the scale factor. It is shown that the total matter can be non-exotic and the violation of the weak energy condition can be avoided.Comment: 11 pages, 1 figure, to appear in Annals of Physic

    Lymphomas in Golestan province of Iran: Results of a population-based cancer registry

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    Introduction: Malignancies of lymphoid cells can be divided into Hodgkin and non-Hodgkin lymphomas (NHL) on the basis of pathologic features, clinical manifestations and treatment. In this paper we present data on lymphomas in Golestan province, in the northeast of Iran, during 2004-2006, using three years results of the Golestan population-based cancer registry (GPCR), a voting member of the International Association of Cancer Registries (IACR). Methods: GPCR started collecting data on all cancers from all public and private diagnostic and therapeutic centers (hospitals, specialist physicians' offices, pathology, laboratory, and imaging centers) of Golestan province in 2004. Here, we used the Iranian national census data to identify the population characteristics of this geographical area. The last census was done in 2006 and the next one will be done in 2011. The population data for years between the national census intervals are retrieved from provincial census done annually by health deputy of Golestan University of Medical Sciences (GOUMS). Results: A total of 5,076 cancer cases were diagnosed in the GPCR between 2004 and 2006. Of these, 237 (4.67 %) were lymphomas, among the ten top cancers of this area, the patients having a mean (±SD) age of 45.2 (±20.9) years. The number of cases, frequency, age specific rates, crude rates and age standardized incidence rates (ASR) (per 100,000 personyears) for lymphomas in males and females are presented. Conclusion: It could be concluded that according to available therapies for HL and NHL, the outcome of the patients could be improved in this area, due to the better diagnostic and therapeutic methods now available

    Avalanche frontiers in dissipative abelian sandpile model as off-critical SLE(2)

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    Avalanche frontiers in Abelian Sandpile Model (ASM) are random simple curves whose continuum limit is known to be a Schramm-Loewner Evolution (SLE) with diffusivity parameter κ=2\kappa = 2. In this paper we consider the dissipative ASM and study the statistics of the avalanche and wave frontiers for various rates of dissipation. We examine the scaling behavior of a number of functions such as the correlation length, the exponent of distribution function of loop lengths and gyration radius defined for waves and avalanches. We find that they do scale with the rate of dissipation. Two significant length scales are observed. For length scales much smaller than the correlation length, these curves show properties close to the critical curves and the corresponding diffusivity parameter is nearly the same as the critical limit. We interpret this as the ultra violet (UV) limit where κ=2\kappa = 2 corresponding to c=2c=-2. For length scales much larger than the correlation length we find that the avalanche frontiers tend to Self-Avoiding Walk, the corresponding driving function is proportional to the Brownian motion with the diffusion parameter κ=8/3\kappa =8/3 corresponding to a field theory with c=0c = 0. This is the infra red (IR) limit. Correspondingly the central charge decreases from the IR to the UV point.Comment: 11 Pages, 6 Figure
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