2,900 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

    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

    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

    Water quality determination in Khuzestan creeks, northwest of Persian Gulf using WQS Index

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    Water quality was studied in Mahshahr creeks from 2005-2006. Due to special characteristics of Mahshahr creeks, high fisheries potential and sever exploitation and human pressure, WQS index was selected for determination of ecological health status of the area. Eight creeks Ghannam, Zasngy, Doragh,Ahmady, Darvish, Patil, Ghazaleh and Bihad were selected and monthly sampling of physical and chemical parameters was done by bottle sampler. Six primary water quality parameters were used to develop an integrated measure of overall water quality. The parameters included Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD _(5)), Total nitrogen (TN), Total phosphorus (TP), pH and Ammonia (NH_3). The results of two ways ANOVA showed that differences were significant only for nitrite between seasons and for pH, ammonium, nitrite and total phosphorus between creeks. Based on index description, parameters pH, NH_ and DO were placed in grade five indicating good quality for water. Total nitrogen was in grade three indicating poor quality and BOD5 and total phosphor were in grade one showing bad quality for water. According to the index, high similarity was found in studied creeks and the total value was found to be 3.33 for the whole studied area, indicating poor water quality

    Mucocutaneous manifestations and nail changes in patients with end-stage renal disease on hemodialysis.

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    Mucocutaneous manifestations are common among patients on hemodialysis (HD). This study was undertaken to determine the prevalence of mucocutaneous manifestations in patients with end-stage renal disease (ESRD) who are on HD. In this cross-sectional, descriptive and analytic study conducted in 2009, 100 patients on HD at the Five Azar Hospital in Gorgan city were randomly selected. All the patients underwent detailed examination by a dermatologist to look for lesions in the skin, hair, nail and mucous membranes; if felt necessary, biopsy was obtained from the lesions. The findings were statistically analyzed using SPSS-13 software. For evaluation of normality of distribution, Kolmogorov-Smirnov was used, for quantitative variables Mann-Whitney and T-test (abnormal distribution) were used and for qualitative variables, Chi-2 and Fisher were used. In this study, P-value less than 0.05 was considered significant. Fifty-one males and 49 females were enrolled. The mean age was 49 ± 12 years. Diabetes was the most common cause of ESRD. In 95% of the patients, at least one mucocutaneous manifestation was present. Xerosis (78.3%) was the most common lesion, followed by pruritus (39.1%), lentigo (34.8%), skin discoloration (32.6%), leukonychia (32%) and thinning of the nail bed (24%). Xerosis, scaling, lentigo, folliculitis, idiopathic guttate hypopigmentation, leukonychia and half and half nail were associated with age. A significant relationship was seen between duration on dialysis and skin discoloration and leukonychia. Clubbing had a significant association with calcium-phosphorus product (Ca � P). There was a significant association between serum ferritin level and pruritus and tinea versicolor lesions. Our study shows that mucocutaneous manifestations are common among patients with ESRD. Identification of these manifestations and their association with causative factors are useful for preventing the lesions
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