A review of elliptical and disc galaxy structure, and modern scaling laws

A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201

Is high body fat estimated by body mass index and waist circumference a predictor of hypertension in adults? A population-based study

BACKGROUND: The aim of this study was to assess the predictive capacity of body fat percentage (%BF) estimated by equations using body mass index (BMI) and waist circumference (WC) to identify hypertension and estimate measures of association between high %BF and hypertension in adults. METHODS: This is a cross-sectional population-based study conducted with 1,720 adults (20–59 years) from Florianopolis, southern Brazil. The area under the ROC curve, sensitivity, specificity, predictive values, and likelihood ratios of cutoffs for %BF were calculated. The association between %BF and hypertension was analyzed using Poisson regression, estimating the unadjusted and adjusted prevalence ratios and 95% CI. RESULTS: The %BF equations showed good discriminatory power for hypertension (area under the ROC curve > 0.50). Considering the entire sample, the cutoffs for %BF with better properties for screening hypertension were identified in the equation with BMI for men (%BF = 20.4) and with WC for women (%BF = 34.1). Adults with high %BF had a higher prevalence of hypertension. CONCLUSIONS: The use of simple anthropometric measurements allowed identifying the %BF, diagnosing obesity, and screening people at risk of hypertension in order to refer them for more careful diagnostic evaluation.Diego Augusto Santos Silva, Edio Luiz Petroski and Marco Aurelio Pere

Reference data for ultrasound bone characteristics in Hungarian children aged 7–19 years

Backround: Osteoporosis is a common disease and physical activity (PA) has a favourable influence on bone status. Aim: To establish normative data for calcaneal quantitative ultrasound (QUS) bone characteristics in children and to analyse the relationships between PA, anthropometric and bone parameters. Subjects and methods: Hungarian children aged 7–19 (n = 2674; 1325 girls, 1349 boys) provided PA, anthropometric and bone data. QUS parameters were registered with Sonost3000 densitometer (speed of sound: SOS, m/s; broadband ultrasound attenuation: BUA, dB/MHz; bone quantity index (BQI = αSOS + βBUA). Reference centiles of QUS parameters were constructed by LMS method. Multivariate linear regression models were used to analyse the relationships. Results: QUS bone parameters increased with age. There were no gender differences, except in 11- and 19-year-old children, where boys showed higher values. SOS (1497.15 ± 15.72 vs 1494.05 ± 14.81 m/s) and BQI (65.31 ± 16.71 vs 62.26 ± 15.78) were higher in athletic children. The regression model revealed significant relations between SOS and age, relative muscle mass and PA; BUA correlated with gender, morphological age, BMI, relative muscle mass and PA. Conclusions: Changes in the bone parameters among 7–19-year-old Hungarian children depended on age, anthropometric dimensions and the level of PA. The normative data could be used for monitoring QUS bone parameters in children, leading to more effective interventions for healthy bones

Sex steroids, bone turnover and bone mineral density in pre-, peri-, and postmenopausal women

To examine 1) the relationships between endogenous androgens and bone mineral density (BMD), 2) the relationships between sex-hormone binding globulin (SHBG) and BMD, and 3) the associations of endogenous androgens and SHBG with biochemical markers of bone turnover, a cross-sectional study was carried out in 88 healthy pre-, peri-, and postmenopausal women aged 35 to 74. Measurements of BMDs at the ultradistal radius and ulna, and the distal radius (using DEXA), estrogens, androgens, deoxypyridinoline (D-Pyr) and intact bone gla protein (I-BGP) were performed. In the multivariate regression models testosterone (T) was positively correlated with BMD at the ultradistal radius and ulna in perimenopausal women, and was positively correlated with BMD at the ultradistal radius and ulna, and the distal radius in postmenopausal women. T was positively associated with I-BGP in premenopausal women (r = 0.65, p < 0.01), and negatively associated with D-Pyr in pre- (r = -0.53, p < 0.05) and postmenopausal women (r = -0.49, p < 0.001). On the other hand, SHBG was negatively correlated with BMD at die ultradistal radius and ulna, and die distal radius in pre- and postmenopausal women in the models. SHBG was positively related to D-Pyr in pre(r = 0.57, p < 0.05) and postmenopausal women (r = 0.41, p < 0.01), and negatively related to I-BGP in postmenopausal women (r = -0.38, p < 0.01). These findings suggest that endogenous androgens may exert positive influences on BMD, and that SHBG may have negative effects on BMD