Evolution of Field Dwarf Galaxies with GEMS

We present a study of the evolution of late-type field dwarfs over the last ~ 1.9 Gyr, based on HST ACS observations carried out as part of the GEMS survey. This study is amongst the first to probe the evolution of dwarfs over such a large timescale. The comparison of structural properties, particularly size and scale length, indicates that the dwarfs in the redshift range z ~ 0.01 to 0.15 (look-back times up to 1.9 Gyr) are more extended than local dwarfs. We argue that this difference is due to the star formation activity becoming more centrally concentrated in late-type dwarfs over the last ~ 1.9 Gyr. We discuss several possible causes for this evolution. We also find a lack of blue compact dwarfs in the GEMS sample and interpret this as indicative of the fact that strong, centrally concentrated star formation is a feature of evolved dwarfs that are entering their final stages of evolution.Comment: 4 pages, to appear in the proceedings of IAUC198: Near-Field Cosmology with Dwarf Elliptical Galaxies, Helmut Jerjen and Bruno Binggeli, ed

Bars in Disk-Dominated and Bulge-Dominated Galaxies at z~0: New Insights from ~3600 SDSS Galaxies

We present a study of large-scale bars in the local Universe, based on a large sample of ~3692 galaxies, with -18.5 <= M_g < -22.0 mag and redshift 0.01 <= z < 0.03, drawn from the Sloan Digitized Sky Survey. Our sample includes many galaxies that are disk-dominated and of late Hubble types. Both color cuts and S\'ersic cuts yield a similar sample of ~2000 disk galaxies. We characterize bars and disks by ellipse-fitting r-band images and applying quantitative criteria. After excluding highly inclined ($>60^{\circ}$) systems, we find the following results. (1) The optical r-band fraction (f_opt-r) of barred galaxies, when averaged over the whole sample, is ~48%-52%. (2) When galaxies are separated according to half light radius (r_e), or normalized r_e/R_24, which is a measure of the bulge-to-disk (B/D) ratio, a remarkable result is seen: f_opt-r rises sharply, from ~40% in galaxies that have small r_e/R_24 and visually appear to host prominent bulges, to ~70% for galaxies that have large r_e/R_24 and appear disk-dominated. (3) $f_{\rm opt-r}$ rises for galaxies with bluer colors (by ~30%) and lower masses (by ~15%-20%). (4) While hierarchical $\Lambda$CDM models of galaxy evolution models fail to produce galaxies without classical bulges, our study finds that ~20% of disk galaxies appear to be ``quasi-bulgeless''. (5) After applying the same cutoffs in magnitude (M_V= 1.5 kpc), and bar ellipticity (e_bar >=~0.4) that studies out to z~1 apply to ensure a complete sample, adequate spatial resolution, and reliable bar identification, we obtain an optical r-band bar fraction of 34%. This is comparable to the value reported at z~0.2-1.0, implying that the optical bar fraction does not decline dramatically by an order of magnitude in bright galaxies out to z~1. (abridged)Comment: accepted for publication in ApJ, 50 pages, 20 figure

Evaluating the role of Kinesiology, as an adjunct therapy, in the management of patients with Crohn's disease

Bibliography: leaves 132-154.This randomized controlled experimental study was designed to determine whether Kinesiology, as an adjunct to medical therapy, would improve the management of patients with Crohn's disease. One hundred and fifty consecutive Crohn's disease patients, attending the Gastrointestinal Clinic at Groote Schuur Hospital, were randomly assigned to a Kinesiology (n=50) and a Control Group (n=50). In order to assess the effect of physical contact, a third group who received Massage (n=50), was also included. All participants attended their monthly hospital visits and continued taking their prescribed medication

Constraints on Bars in the Local Universe from 5000 SDSS Galaxies

We present the first study of bars in the local Universe, based on the Sloan Digitized Sky Survey (SDSS). The large sample of ~5000 local galaxies provides the largest study to date of local bars and minimizes the effect of cosmic variance. The sample galaxies have M_g<=-18.5 mag and cover the redshift range 0.01<=z<0.04. We use a color cut in the color-magnitude diagram and the Sersic index n to identify disk galaxies. We characterize bars and disks using r-band images and the method of iterative ellipse fits and quantitative criteria developed in Jogee at al. (2004, ApJL, 615, L105). After excluding highly inclined (i>60 degrees) systems our results are: (1) the optical (r-band) fraction of barred galaxies among local disk galaxies is 43%, which confirms the ubiquity of local bars, in agreement with other optical studies based on smaller samples (e.g.Eskridge et al. 2000, AJ, 119, 536, Marinova & Jogee 2006, astro-ph/0608039); (2) the optical bar fraction rises for bluer galaxies, suggesting a relation between bars and star formation; (3) preliminary analyzes suggest that the optical bar fraction increases steeply with the galaxy effective radius; (4) the optical bar fraction at z~0 is ~35% for bright disks (M_g0.4), large-scale (bar semi-major axis >1.5 kpc) bars, which is comparable to the value of 30+/-6% reported earlier (Jogee et al. 2004) for similar disks and bars at z~0.2-1.0.Comment: 1 page, Proceedings of the IAU Symposium No. 235, 2006, "Galaxy Evolution across the Hubble Time", F. Combes & J. Palous, ed

Bulge n and B/T in High Mass Galaxies: Constraints on the Origin of Bulges in Hierarchical Models

We use the bulge Sersic index n and bulge-to-total ratio (B/T) to explore the fundamental question of how bulges form. We perform 2D bulge-disk-bar decomposition on H-band images of 143 bright, high stellar mass (>1.0e10 solar masses) low-to-moderately inclined (i<70 degrees) spirals. Our results are: (1) Our H-band bar fraction (~58%) is consistent with that from ellipse fits. (2) 70% of the stellar mass is in disks, 10% in bars, and 20% in bulges. (3) A large fraction (~69%) of bright spirals have B/T<0.2, and ~76% have low n<2 bulges. These bulges exist in barred and unbarred galaxies across a wide range of Hubble types. (4) About 65% (68%) of bright spirals with n<2 (B/T<0.2) bulges host bars, suggesting a possible link between bars and bulges. (5) We compare the results with predictions from a set of LCDM models. In the models, a high mass spiral can have a bulge with a present-day low B/T<0.2 only if it did not undergo a major merger since z<2. The predicted fraction (~1.6%) of high mass spirals, which have undergone a major merger since z<4 and host a bulge with a present-day low B/T<0.2, is a factor of over thirty smaller than the observed fraction (~66%) of high mass spirals with B/T<0.2. Thus, contrary to common perception, bulges built via major mergers since z<4 seriously fail to account for the bulges present in ~66% of high mass spirals. Most of these present-day low B/T<0.2 bulges are likely to have been built by a combination of minor mergers and/or secular processes since z<4.Comment: Accepted by the Astrophysical Journal. 42 pages of text, 27 figures, 12 table

Is there room for religious ethics in South African abortion law?

In light of the prominence and influence of secular bioethics, one could argue that religious ethics concerning weighty medical ethical issues such as abortion are often overlooked. South Africa (SA) is one of just five African countries which have legalised abortion without undue restriction, notwithstanding its gestational restrictions, placing it among the countries with the most liberal abortion laws in Africa.[1] More than 94% of South Africans are religious, predominantly following Christianity, African Traditional Religion, Islam, Judaism and Hinduism.[2] This raises the question of whether contemporary abortion law is inclusive of the religious ethical values that dictate the lives of the great majority of citizens. This article will explore religious ethics and secular morality in SA, followed by a discussion of the legal status of the fetus and contemporary abortion legislation. Subsequently, this article will determine whether the law is inclusive of religious ethical views on abortion, and if so, how

Partial-birth abortion – is it legally and ethically justifiable? Lessons for South Africa

Intact dilation and extraction is a surgical abortion procedure dubbed ‘partial-birth abortion’, and is deemed infanticide by conservative pro-life advocates in the USA. Despite its salutary (albeit feticidal) nature, as it is arguably less destructive than alternative surgical abortion procedures, intact dilation and extraction is federally banned in the USA. While ostensibly unrelated, the matter is germane to South Africa (SA) as it may inform legislation and legal policy on the regulation of feticidal abortion procedures, since feticide remains unregulated by law. The objective of this article is to understand why intact dilation and extraction is proscribed, and whether proscription is justifiable in SA. Accordingly, the primary legal, medical and ethical arguments underpinning proscription are presented, followed by an examination of the veracity of each argument before gauging whether intact dilation and extraction is constitutionally and ethically justifiable in SA