2,220 research outputs found

    Tailed Radio Galaxies as Probes of Cluster Physics in the Square Kilometre Array Era

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    In recent years, the use of tailed radio galaxies as environmental probes has gained momentum as a method for galaxy cluster detection, examining the dynamics of individual clusters, measuring the density and velocity flows in the intra-cluster medium, and for probing cluster magnetic fields. To date instrumental limitations in terms of resolution and sensitivity have confined this research to the local (z < 0.7) Universe. The advent of SKA-1 surveys however will allow detection of well over 1 million tailed radio galaxies and their associated galaxy clusters out to redshifts of 2 or more. This is in fact ten times more than the current number of known clusters in the Universe. Such a substantial sample of tailed galaxies will provide an invaluable tool not only for detecting clusters, but also for characterizing their intra-cluster medium, magnetic fields and dynamical state as a function of cosmic time. In this paper we present an analysis of the usability of tailed radio galaxies as tracers of dense environments extrapolated from existing deep radio surveys such the Extended Chandra Deep Field-South.Comment: 4 pages, 2 figures, in URSI GASS (XXXIth) held 16-23 August 2014, Beijing, China. Published as AIP Conference Proceeding

    An approximation algorithm for the solution of the nonlinear Lane-Emden type equations arising in astrophysics using Hermite functions collocation method

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    In this paper we propose a collocation method for solving some well-known classes of Lane-Emden type equations which are nonlinear ordinary differential equations on the semi-infinite domain. They are categorized as singular initial value problems. The proposed approach is based on a Hermite function collocation (HFC) method. To illustrate the reliability of the method, some special cases of the equations are solved as test examples. The new method reduces the solution of a problem to the solution of a system of algebraic equations. Hermite functions have prefect properties that make them useful to achieve this goal. We compare the present work with some well-known results and show that the new method is efficient and applicable.Comment: 34 pages, 13 figures, Published in "Computer Physics Communications

    Translation and validation of the Persian version of the treatment adherence questionnaire for patients with hypertension

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    BACKGROUND: Hypertension is a global public health crisis. Poorly controlled high blood pressure is one of the major factors contributed to this crisis. As lack of treatment adherence is often considered the main reason for this failure, the Treatment Adherence Questionnaire for Patient with Hypertension (TAQPH) was developed. Since this questionnaire should be reliable and strongly valid to be used in clinics and research, this study was performed to test the reliability and validity of the TAQPH. METHODS: A cross-sectional study was conducted to validate the Persian version of TAQPH after using a modified forward/backward translation procedure. A total of 330 hypertensive patients were participated in this study. Construct and criterion validity, Cronbach¢s alpha, and test-retest reliability were used to validate the Persian scale. RESULTS: Data analysis showed that the scale had excellent stability (intraclass correlation = 0.95) and good acceptability of internal consistency (α = 0.80). The exploratory factor analysis (EFA) was meaningful but was not confirmed with confirmatory factor analysis (CFA). The scale score was correlated with Morisky Medication Adherence Scale (MMAS) score (Ρ = 0.27). CONCLUSION: In total, most of the psychometric properties of the 25-item P-TAQHP achieved the standard level and were sufficient to recommend for general use

    Small Cell City

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    Traditionally, mobile operators have planned their networks to accommodate mobile terminals at ground level. Increasingly, mobile users communicate while stationary from within high-rise buildings. With mobiles operating at a variety of different heights and mobilities, plus the requirement to accommodate increasing teletraffic and multimedia services, there is a need to compact small cells into the three-dimensional city space. This article is concerned with using city buildings to act as electromagnetic molds that define the size and shape of each three-dimensional cell. Issues related to using these cells to form a mobile radio network are discussed
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