Clusters of galaxies have been extensively used to determine cosmological parameters. A major difficulty in making the best use of Sunyaev-Zel'dovich (SZ) and X-ray observations of clusters for ...cosmology is that using X-ray observations it is difficult to measure the temperature distribution and therefore determine the density distribution in individual clusters of galaxies out to the virial radius. Observations with the new generation of SZ instruments are a promising alternative approach. We use clusters of galaxies drawn from high-resolution adaptive mesh refinement cosmological simulations to study how well we should be able to constrain the large-scale distribution of the intracluster gas (ICG) in individual massive relaxed clusters using AMiBA in its configuration with 13 1.2 m diameter dishes (AMiBA13) along with X-ray observations. We show that non-isothermal Delta *b models provide a good description of the ICG in our simulated relaxed clusters. We use simulated X-ray observations to estimate the quality of constraints on the distribution of gas density, and simulated SZ visibilities (AMiBA13 observations) for constraints on the large-scale temperature distribution of the ICG. We find that AMiBA13 visibilities should constrain the scale radius of the temperature distribution to about 50% accuracy. We conclude that the upgraded AMiBA, AMiBA13, should be a powerful instrument to constrain the large-scale distribution of the ICG.
Serum lipoprotein (a) (Lpa) has been associated with coronary artery atherosclerosis. Its association with restenosis after percutaneous transluminal coronary angioplasty (PTCA) has not been ...previously studied. Serum levels of Lp(a), in addition to other lipoproteins, and their components using standard assays, were determined in subjects undergoing cardiac catheterization within 10 months after PTCA. Clinical (e.g., sex, diabetes, angina class) and angiographic (e.g., PTCA percent diameter reduction) factors were not different between the group without (diameter reduction less than 50%; group A) and the group with (diameter reduction greater than or equal to 50%; Group B) restenosis. Total cholesterol, triglycerides, high- and low-density lipoprotein cholesterol, apolipoprotein A-I, apolipoprotein B and Lp(a) were compared. Univariate predictors of restenosis were serum triglycerides (2.50 +/- 1.07 mmol/liter for group A vs 1.72 +/- 0.79 +/- mmol/litre for group B, p = 0.008), and Lp(a) (median: 7.0 mg/dl range 0 to 44 for group A vs 19 mg/dl range 1 to 120 for group B; p = 0.006). Stepwise logistic regression revealed the only significant independent predictor of restenosis to be serum Lp(a) (p = 0.018). Each quintile of Lp(a) was associated with a progressively higher risk of restenosis, with the highest quintile (40 to 120 mg/dl) having an odds ratio of 11 (95% confidence interval 9 to 13) compared with the lowest quintile (0 to 3.9 mg/dl) (p = 0.033). A serum Lp(a) of greater than 19 mg/dl was associated with an odds ratio of 5.9 (95% confidence interval 4.6 to 7.2) (restenosis rates of 58% in the group with 0 to 19 mg/dl and 89% in the group with 19 to 120 mg/dl; p = 0.006).
The causal link between therapeutic irradiation and malignant melanoma has not been firmly established. The authors report a novel case of a malignant melanoma arising from a therapeutically ...irradiated neovagina reconstructed from skin flaps following radical vulvectomy with inguinal lymph node dissection 16 years earlier. The diagnosis was established by light microscopy and immunohistochemical staining. Reports of melanoma arising from sites of previous radiation therapy are reviewed. Our observations suggest that therapeutic radiation may be a factor in the development of malignant melanoma, particularly in non-sun-exposed areas, including the genital tract.
Cold dark matter (CDM) hierarchical structure formation models predict the existence of large-scale accretion shocks between the virial and turnaround radii of clusters of galaxies. Kocsis et al. ...(2005) suggest that the Sunyaev-Zel'dovich (SZ) signal associated with such shocks might be observable with the next generation radio interferometer, ALMA. We study the three--dimensional distribution of accretion shocks around individual clusters of galaxies drawn from adaptive mesh refinement (AMR) and smoothed particle hydrodynamics (SPH) simulations of LCDM (dark energy dominated CDM) models. In relaxed clusters, we find two distinct sets of shocks. One set ("virial shocks"), with Mach numbers of 2.5-4, is located at radii 0.9-1.3 Rvir, where Rvir is the spherical infall estimate of the virial radius, covering about 40-50% of the total surface area around clusters at these radii. Another set of stronger shocks ("external shocks") is located farther out, at about 3 Rvir, with large Mach numbers (~100), covering about 40-60% of the surface area. We simulate SZ surface brightness maps of relaxed massive galaxy clusters drawn from high resolution AMR runs, and conclude that ALMA should be capable of detecting the virial shocks in massive clusters of galaxies. More simulations are needed to improve estimates of astrophysical noise and to determine optimal observational strategies.
Accurate mass determination of clusters of galaxies is crucial if they are to be used as cosmological probes. However, there are some discrepancies between cluster masses determined based on ...gravitational lensing, and X-ray observations assuming strict hydrostatic equilibirium (i.e., the equilibrium gas pressure is provided entirely by thermal pressure). Cosmological simulations suggest that turbulent gas motions remaining from hierarchical structure formation may provide a significant contribution to the equilibrium pressure in clusters. We analyze a sample of massive clusters of galaxies drawn from high resolution cosmological simulations, and find a significant contribution (20%-45%) from non-thermal pressure near the center of relaxed clusters, and, in accord with previous studies, a minimum contribution at about 0.1 Rvir, growing to about 30%-45% at the virial radius, Rvir. Our results strongly suggest that relaxed clusters should have significant non-thermal support in their core region. As an example, we test the validity of strict hydrostatic equilibirium in the well-studied massive galaxy cluster Abell 1689 using the latest high resolution gravitational lensing and X-ray observations. We find a contribution of about 40% from non-thermal pressure within the core region of A1689, suggesting an alternate explanation for the mass discrepancy: the strict hydrostatic equilibirium is not valid in this region.
Does serum LP(a) predict restenosis after PTCA? Hearn, James A.; Donohue, Bryan C.; King, Spencer B. ...
Journal of the American College of Cardiology,
February 1990, 1990-02-00, Letnik:
15, Številka:
2
Journal Article
Clusters of galaxies have been used extensively to determine cosmological parameters. A major difficulty in making best use of Sunyaev-Zel'dovich (SZ) and X-ray observations of clusters for cosmology ...is that using X-ray observations it is difficult to measure the temperature distribution and therefore determine the density distribution in individual clusters of galaxies out to the virial radius. Observations with the new generation of SZ instruments are a promising alternative approach. We use clusters of galaxies drawn from high-resolution adaptive mesh refinement (AMR) cosmological simulations to study how well we should be able to constrain the large-scale distribution of the intra-cluster gas (ICG) in individual massive relaxed clusters using AMiBA in its configuration with 13 1.2-m diameter dishes (AMiBA13) along with X-ray observations. We show that non-isothermal beta models provide a good description of the ICG in our simulated relaxed clusters. We use simulated X-ray observations to estimate the quality of constraints on the distribution of gas density, and simulated SZ visibilities (AMiBA13 observations) for constraints on the large-scale temperature distribution of the ICG. We find that AMiBA13 visibilities should constrain the scale radius of the temperature distribution to about 50% accuracy. We conclude that the upgraded AMiBA, AMiBA13, should be a powerful instrument to constrain the large-scale distribution of the ICG.
Tag-recovery Models JOHN M. HOENIG; KENNETH H. POLLOCK; WILLIAM HEARN
Handbook of Capture-Recapture Analysis,
10/2005
Book Chapter
Modern tagging models for estimating mortality rates of exploited populations derive from the work of Seber (1970), Brownie (1973), Youngs and Robson (1975), and Brownie et al. (1985). These models ...pertain to the case where tagged animals are killed when they are recaptured and there is no direct information on animals that die of natural causes (such as empty shells of mollusks). The authors cited above concentrated on the estimation of the annual survival rate, S, which is the probability that an animal alive at the start of the year will survive to the end of the year. These models
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