469 research outputs found

    Comments on "The long-period Galactic Cepheid RS Puppis. I. A geometric distance from its light echoes"

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    The luminous Galactic Cepheid RS Puppis is unique in being surrounded by a dust nebula illuminated by the variable light of the Cepheid. In a recent paper in this journal, Kervella et al. (2008) report a very precise geometric distance to RS Pup, based on measured phase lags of the light variations of individual knots in the reflection nebula. In this commentary, we examine the validity of the distance measurement, as well as the reality of the spatial structure of the nebula determined by Feast (2008) based upon the phase lags of the knots. {Kervella et al. assumed that the illuminated dust knots lie, on average, in the plane of the sky (otherwise it is not possible to derive a geometric distance from direct imaging of light echoes). We consider the biasing introduced by the high efficiency of forward scattering. We conclude that most of the knots are in fact likely to lie in front of the plane of the sky, thus invalidating the Kervella et al. result. We also show that the flat equatorial disk structure determined by Feast is unlikely; instead, the morphology of the nebula is more probably bipolar, with a significant tilt of its axis with respect to the plane of the sky. Although the Kervella et al. distance result is invalidated, we show that high-resolution polarimetric imaging has the potential to yield a valid geometric distance to this important Cepheid.Comment: 10 pages, 5 figures, 1 table; accepted by Astronomy & Astrophysic

    SOME PROPERTIES OF C-FRAMES OF SUBSPACES

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    Abstract. In [13] frames of subspaces extended to continuous version namely c-frame of subspaces. In this article we consider to the relations between c-frames of subspaces and local c-frames. Also in this article we give some important relation about duality and parseval c-frames of subspaces. 1. Introduction an

    Health needs of clients as reported by medical practitioners from two districts of Sindh

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    Objective: To identify the major health and reproductive health problems for which people consult local medical practitioners.METHODOLOGY: Forty-one practitioners completed a self-administered questionnaire. A startified purposive sample of practitioners was selected by asking the community members from various towns and rural areas to identify practitioners who have most busy practices and are perceived as providing quality care.Results: Nine of the forty-one practitioners were females. Twenty-two were consulted mainly by women and another seventeen by an equal number of women and men. Practitioners pointed to malnutrition, malaria, gastrointestinal and respiratory tract problems as being the most common ailments. They identified menstrual problems, malnutrition among pregnant women, burning micturition and vaginal discharge as the most common reproductive health problems of their clients. Only 16 medical practitioners said that they diagnosed someone in the last one-month as suffering from sexually transmitted infections.CONCLUSION: The survey helped in developing an understanding of health issues from provider perspective. Findings indicate a concordance between what has been revealed by previous population based studies in similar situations and to what health problems practitioners pointed as common. While a comprehensive needs-assessment requires surveys and qualitative interviews with communities, consultations with relatively fewer medical practitioners could also provide a quick and fair approximation of priority health problems in the area

    Bladder injury during infected tola hip arthroplasty prosthesis removal: Report of a case and review of the literature

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    The bladder is the most frequently injured organ during pelvic surgery. However, during hip surgery, this complication is extremely rare. We report a case of bladder injury during total hip arthroplasty prosthesis removal surgery. A 65-year-old male was admitted to our hospital with left hip pain and wound infection. On plain radiograms, acetabular protrusion was identified. We decided to remove protruzed acetabular cup and place spacer. During the operation, unexpectedly bladder injury occurred. The rupture was sutured intraoperatively. We left a catheter in the bladder after internal urethrotomy to drain the urine.Keywords: Arthroplasty, Bladder injury, Cystogram, Hip prosthesis removal, Infectio

    Probability densities for the sums of iterates of the sine-circle map in the vicinity of the quasi-periodic edge of chaos

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    We investigate the probability density of rescaled sum of iterates of sine-circle map within quasi-periodic route to chaos. When the dynamical system is strongly mixing (i.e., ergodic), standard Central Limit Theorem (CLT) is expected to be valid, but at the edge of chaos where iterates have strong correlations, the standard CLT is not necessarily to be valid anymore. We discuss here the main characteristics of the central limit behavior of deterministic dynamical systems which exhibit quasi-periodic route to chaos. At the golden-mean onset of chaos for the sine-circle map, we numerically verify that the probability density appears to converge to a q-Gaussian with q<1 as the golden mean value is approached.Comment: 7 pages, 7 figures, 1 tabl

    Implications of genetic variation of common drug metabolizing enzymes and ABC transporters among the Pakistani population

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    Genetic polymorphism of drug metabolizing enzymes and transporters may influence drug response. The frequency varies substantially between ethnicities thus having implications on appropriate selection and dosage of various drugs in different populations. The distribution of genetic polymorphisms in healthy Pakistanis has so far not been described. In this study, 155 healthy adults (98 females) were included from all districts of Karachi. DNA was extracted from saliva and genotyped for relevant SNVs in CYP1A1, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4 and CYP3A5 as well as ALDH3A1, GSTA1, ABCB1 and ABCC2. About 64% of the participants were born to parents who were unrelated to each other. There was generally a higher prevalence (p \u3c 0.05) of variant alleles of CYP450 1A2, 2B6, 2C19, 3A5, ALDH3A1, GSTM1 as well as ABCB1 and ABCC2 in this study cohort than in other ethnicities reported in the HapMap database. In contrast, the prevalence of variant alleles was lower in GSTA1. Therefore, in the Pakistani population sample from Karachi a significantly different prevalence of variant drug metabolizing enzymes and ABC transporters was observed as compared to other ethnicities, which could have putative clinical consequences on drug efficacy and safety

    Modeling supersonic heated jet noise at fixed jet Mach number using an asymptotic approach for the acoustic analogy Green’s function and an optimized turbulence model

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    In this study we show how accurate jet noise predictions can be achieved within Goldstein’s generalized acoustic analogy formulation for heated and un-heated supersonic jets using a previously developed asymptotic theory for the adjoint vector Green’s function and a turbulence model whose independent parameters are determined using an optimization algorithm . In this approach, mean flow non-parallelism enters the lowest order dominant balance producing enhanced amplification at low frequencies, which we believe corresponds to the peak sound at small polar observation angles. The novel aspect of this paper is that we exploit both mean flow and turbulence structure from existent Large Eddy Simulations database of two axi-symmetric round jets at fixed jet Mach number and different nozzle temperature ratios to show (broadly speaking) the efficacy of the asymptotic approach. The empirical parameters that enter via local turbulence length scales within the algebraic-exponential turbulence model are determined by optimizing against near field turbulence data post-processed from the LES calculation. Our results indicate that accurate jet noise predictions are obtained with this approach up to a Strouhal number of 0.5 for both jets without introducing significant empiricism
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