Keck Studies of M31's Stellar Halo

We present Keck 10-meter/LRIS spectra of candidate red giants in the halo of M31, located at a projected radius of R=19kpc on the minor axis. These spectroscopic targets have been selected using a combination of UBRI-based and morphological screening to eliminate background galaxies. Radial velocity measurements are used to separate M31 halo giants from foreground Milky Way dwarf stars, M31 disk stars, and residual background galaxies. The metallicity of each M31 halo giant is measured using standard photometric and spectroscopic techniques, the latter based on the strength of the CaII triplet. The various [Fe/H] estimates are in rough agreement with one another. The data reveal a large spread (>2dex) in [Fe/H] in M31's halo; there is no strong radial [Fe/H] gradient. LRIS and HIRES spectra are also presented for red giants in five dwarf spheroidal satellites of M31: AndI, AndIII, AndV, AndVI, and AndVII. There appears to be a significant metallicity spread in AndVI and possibly in AndI. The new radial velocity data on these outer dwarfs are used to constrain the total mass of M31: the best estimate is under 10^(12)Msun, somewhat less than the best estimate for the Milky Way.Comment: 12 pages, 7 figures, Proceedings of SPIE Conference: Discoveries and Research Prospects with 8-10 Meter Class Telescopes (Munich March 2000

Introduction to the symposium—Keeping Time During Evolution : Conservation and Innovation of the Circadian Clock

Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Integrative and Comparative Biology 53 (2013): 89-92, doi: 10.1093/icb/ict062.Diurnal and seasonal cues play critical and conserved roles in behavior, physiology, and reproduction in diverse animals. The circadian clock is a transcription-translation feedback loop that represents the molecular mechanism underlying many of these periodic processes, frequently through responses to light. Although much of the core regulatory machinery is deeply conserved among diverse animal lineages, there are also many examples of innovation in the way the clock either is constructed at the molecular-level or deployed in coordinating behavior and physiology. The nine papers contained within this issue address aspects of circadian signaling in diverse taxa, utilize wide-ranging approaches, and collectively provide thought-provoking discussion of future directions in circadian research.The symposium “Keeping Time During Animal Evolution: Conservation and Innovation of the Circadian Clock” was generously supported by the Society of Integrative and Comparative Biology and by Award 1239607 from the Integrative Organismal Systems Program at the National Science Foundation.2014-05-2

Kinematics and Composition of the Galactic Bulge: Recent Progress

We present recent results from a Keck study of the composition of the Galactic bulge, as well as results from the bulge Bulge Radial Velocity Assay (BRAVA). Culminating a 10 year investigation, Fulbright, McWilliam, & Rich (2006, 2007) solved the problem of deriving the iron abundance in the Galactic bulge, and find enhanced alpha element abundances, consistent with the earlier work of McWilliam & Rich (1994). We also report on a radial velocity survey of {\sl 2MASS}-selected M giant stars in the Galactic bulge, observed with the CTIO 4m Hydra multi-object spectrograph. This program is to test dynamical models of the bulge and to search for and map any dynamically cold substructure in the Galactic bulge. We show initial results on fields at $-10^{\circ} < l <+10^{\circ}$ and $b=-4^{\circ}$. We construct a longitude-velocity plot for the bulge stars and the model data, and find that contrary to previous studies, the bulge does not rotate as a solid body; from $-5^{\circ}<l<+5^{\circ}$ the rotation curve has a slope of $\approx 100 km s^{-1}$ and flattens considerably at greater $l$ and reaches a maximum rotation of $45 {km s^{-1}}$ (heliocentric) or $\sim 70 {km s^{-1}}$ (Galactocentric). This rotation is slower than that predicted by the dynamical model of Zhao (1996).Comment: 6 pages, 6 figures, contributed paper at IAU Symposium 245 "Formation and Evolution of Galactic Bulges

The Evolutionary Origin of the Runx/CBFbeta Transcription Factors – Studies of the Most Basal Metazoans

BACKGROUND. Members of the Runx family of transcriptional regulators, which bind DNA as heterodimers with CBFβ, are known to play critical roles in embryonic development in many triploblastic animals such as mammals and insects. They are known to regulate basic developmental processes such as cell fate determination and cellular potency in multiple stem-cell types, including the sensory nerve cell progenitors of ganglia in mammals. RESULTS. In this study, we detect and characterize the hitherto unexplored Runx/CBFβ genes of cnidarians and sponges, two basal animal lineages that are well known for their extensive regenerative capacity. Comparative structural modeling indicates that the Runx-CBFβ-DNA complex from most cnidarians and sponges is highly similar to that found in humans, with changes in the residues involved in Runx-CBFβ dimerization in either of the proteins mirrored by compensatory changes in the binding partner. In situ hybridization studies reveal that Nematostella Runx and CBFβ are expressed predominantly in small isolated foci at the base of the ectoderm of the tentacles in adult animals, possibly representing neurons or their progenitors. CONCLUSION. These results reveal that Runx and CBFβ likely functioned together to regulate transcription in the common ancestor of all metazoans, and the structure of the Runx-CBFβ-DNA complex has remained extremely conserved since the human-sponge divergence. The expression data suggest a hypothesis that these genes may have played a role in nerve cell differentiation or maintenance in the common ancestor of cnidarians and bilaterians.National Science Foundation (IBN-0212773, FP-91656101-0); Boston University SPRInG (20-202-8103-9); Israel Science Foundation (825/07

HPV Awareness, Knowledge and Attitudes among Older African-American Women

Objective: To assess correlates of human papillomavirus (HPV) awareness, knowledge, and attitudes among older, church-going African-American women.ﾠMethods: Participants (N = 759), aged 40-80, answered survey questions about HPV awareness, knowledge, and attitudes toward vaccination of adolescent daughters. Associations between participant characteristics and HPV items were assessed using chi-square tests and logistic regression analyses.ﾠResults: Younger age, higher education, a family history of cancer, and less spirituality were each associated with HPV awareness individually, and when considered jointly in a single model (p values <.038). Higher education was related to HPV knowledge (p = .006).ﾠConclusions: African-American women of older age, less education, no family history of cancer, and/or higher spirituality might benefit from targeted church-based HPV educational campaigns

The Initial-Final Mass Relation: Direct Constraints at the Low Mass End

The initial-final mass relation represents a mapping between the mass of a white dwarf remnant and the mass that the hydrogen burning main-sequence star that created it once had. The relation thus far has been constrained using a sample of ~40 stars in young open clusters, ranging in initial mass from ~2.75 -- 7 Msun, and shows a general trend that connects higher mass main-sequence stars with higher mass white dwarfs. In this paper, we present CFHT/CFH12K photometric and Keck/LRIS multiobject spectroscopic observations of a sample of 22 white dwarfs in two older open clusters, NGC 7789 (t = 1.4 Gyr) and NGC 6819 (t = 2.5 Gyr). We measure masses for the highest S/N spectra by fitting the Balmer lines to atmosphere models and place the first direct constraints on the low mass end of the initial-final mass relation. Our results indicate that the observed general trend at higher masses continues down to low masses, with M_initial = 1.16 Msun main-sequence stars forming M_final = 0.53 Msun white dwarfs (including our data from the very old open cluster, NGC 6791). This extention of the relation represents a four fold increase in the total number of hydrogen burning stars for which the integrated mass loss can now be calculated, assuming a Salpeter initial mass function. The new leverage at the low mass end is used to derive a purely empirical initial-final mass relation without the need for any indirectly derived anchor points. The sample of white dwarfs in these clusters also shows several very interesting systems that we discuss further: a DB (helium atmosphere) white dwarf, a magnetic white dwarf, a DAB (mixed hydrogen/helium atmosphere or a double degenerate DA+DB) white dwarf(s), and two possible equal mass DA double degenerate binary systems.Comment: 18 pages, 12 figures, 3 tables. Submitted to Astrophys. J. Revised from first versio