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

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

Plate tectonic aspects of the Triassic carbonate-hosted stratiform-stratabound base-metal deposits in the Western Balkan, NW Bulgaria

The Triassic carbonate-hosted stratiform-stratabound base-metal deposits in the Western Balkan, NW Bulgaria, have well defined regional geological and tectonic settings, style ofmineralisation, mineralogical, geochemical and isotopic data. Their genesis, however, remains controversial in the framework of plate tectonic models, and is not supported by comparative analysis of possible counterpart candidates within the NW Tethyan domain. Besides, the crucial missing information is the geochronology of ore mineralisation relative to the Triassic carbonate host rocks. The article stresses the ambiguities due to the lack ofmineralisation age dating, and emphasises the necessity for building a convincing plate tectonic model based on the relevant geodynamic setting. A prospective direction of researchis the critical comparison with equivalent sediment-hosted base-metal deposits within the continental margin environments such as those in the Alps and Dinarides as well as others in the Alpine-Himalayan orogen and worldwide.</p

Supporting Pre-Service Primary School Teachers with Hands-on-Science

The education that primary school students receive shapes their relationship with science. Elementary school teachers report they have low confidence and enthusiasm about teaching science. The Hands-on-Science Program at UT Austin was created to serve the unique needs of Applied Learning and Development majors. HoS consists of four required content courses: Physics, Chemistry &amp; Geology, Biology, and Astronomy &amp; Earth Climate. HoS classes differ from traditional science courses in two ways: (1) method of instruction, and (2) content. Our students attain higher learning gains and display improved attitudes towards learning science, compared to students who take traditional science classes

Application of mathematical models to optimization of the methane fermentation of fowl dung

We applied mathematical modeling to the optimization of the methane fermentation of dung obtained from the breeding of farm animals in preceding research we carried out/Baykov, 1987, Baykov & Tyravska, 1991/. In the last few years compost is of greater interest as a resource for increasing soil fertility. The conducted research /Baykov, 1987/ indicates that the compost, obtained from the methane fermentation of fowl dung, is a source of biogenic chemical elements in optimal proportions. In the Ordinance for the organic production of plants /Ordinance №22/2001 of the Ministry of Agriculture and Forestry/ it is stated that the manure that can be used is produced from just a few farms. These are the reasons to carry out a research on optimizing the methane fermentation for a little farm, breeding 5000 laying hens without any litter, by applying mathematical modeling

IMPACT OF NIGHT SHIFT WORK AND LONG WORKING HOURS ON HEALTH OF BULGARIAN PHYSICIANS

Night shift work and long working hours are associated with an increased risk of some chronic diseases like cardiovascular, endocrine, digestive diseases and others. The aim of the study was to follow the impact of night shift work and long working hours on health of Bulgarian physicians. A cross-sectional anonymous survey, comprising 761 physicians of age 44.3±14.1 years, and including information on work place variables, working hours and shift system was carried. The health status questionnaire included a list of 13 groups of diseases diagnosed by a physician. Statistical analyses were carried out with SPSS. 63.7% of the physicians worked rotating shifts, mainly 12- hour shifts (49.7%) and 67.5% had a history of night work. Overtime and multiple work places were common, contributing to long working hours/week with 38.5% working 41–50 hours/week, 27.8% - 51–60 hours/week and 13.7% - >61 hours/week. Results showed that the highest rate of cardiovascular diseases was in ex night shift workers both for males (F=18.728, p61 hours/week, except for the rate of cardiovascular diseases in female physicians, the highest in those working 20-40 hours/week. Work schedule was a predictor of cardiovascular diseases and mental disorders; history of night work was a predictor of digestive diseases. Our data contribute to the evidence that night shift work and long working hours increase health risk

Divergent drift of Adriatic-Dinaridic and Moesian carbonate platforms during the rifting phase witnessed by triassic MVT Pb-Zn and SEDEX deposits; a metallogenic approach

Early-intracontinental rifting of Pangea is result of thermal doming in Uppermost Permian time giving rise to the formation of horst-graben  structures, followed by slow subsidence, marine transgression and evaporate deposition. Consequence of incipient magmatism are numerous geothermal fields and subterrestrial hydrothermal siderite-barite-polysulfide deposits (PALINKAŠ et al, this issue). Advanced rifting magmatism as a successive stage in Middle Triassic brought intensive submarine volcanism, accompanied by coeval sedimentation of chert and siliciclastics, building up volcanogenic-sedimentary formations. Volcanic activity with explosive phases and generation of large volumes of pyroclastic rocks in the rifts produced concomitant mineralization with numerous SEDEX deposits of Fe-Mn-Ba-polysulfides. Passive continental margins flanked by the Adria-Dinaridic carbonate platform as passive continental margin of the northern Gondwanaland and Moesian carbonate platform, as a counterpart on the European passive continental margin, were divergently drifted in the coarse of the advanced rifting. A fast growing carbonate platforms, developing gradually, covered  evidences of the earlier intracontinental rifting and their ore formations. On the other hand, the carbonate platforms themselves host specific Pb-Zn deposit, well known as Mississippi valley type, (MVT) or Bleiberg-Mežica type according the traditional european terminology. Triassic MVT and SEDEX deposits are symmetrically situated on the both sides of the divergent passive margins in this early history of the Tethyan ocean.</p

Characterizing Bars at z~0 in the optical and NIR: Implications for the Evolution of Barred Disks with Redshift

Critical insights on galaxy evolution stem from the study of bars. With the advent of HST surveys that trace bars in the rest-frame optical out to z~1, it is critical to provide a reference baseline for bars at z~0 in the optical band. We present results on bars at z~0 in the optical and NIR bands based on 180 spirals from OSUBSGS. (1) The deprojected bar fraction at z~0 is ~60% +/-6% in the NIR H-band and ~44% +/-6% in the optical B-band. (2) The results before and after deprojection are similar, which is encouraging for high-redshift studies that forego deprojection. (3) Studies of bars at z~0.2-1.0 (lookback time of 3-8 Gyr) have reported an optical bar fraction of ~30% +/-6%, after applying cutoffs in absolute magnitude (M_V = 1.5 kpc), and bar ellipticity (e_bar >= 0.4). Applying these exact cutoffs to the OSUBSGS data yields a comparable optical B-band bar fraction at z~0 of ~ 34%+/-6%. This rules out scenarios where the optical bar fraction in bright disks declines strongly with redshift. (4) Most (~70%) bars have moderate to high strentgh or ellipticity (0.50 <= e_bar <= 0.75). There is no bimodality in the distribution of e_bar. The H-band bar fraction and e_bar show no substantial variation across RC3 Hubble types Sa to Scd. (5) RC3 bar types should be used with caution. Many galaxies with RC3 types "AB" turn out to be unbarred and RC3 bar classes "B" and "AB" have a significant overlap in e_bar. (6) Most bars have sizes below 5 kpc. Bar and disk sizes correlate, and most bars have a_bar/R_25~0.1-0.5. This suggests that the growths of bars and disks are intimately tied.Comment: 11 pages, 17 figures, 3 tables, ApJ accepted, abridged abstract below. Minor changes and shortened paper for ApJ limits. For high resolution figures see http://www.as.utexas.edu/~marinova/paper1-highres.pd