The Tidal Tails of 47 Tucanae

The Galactic globular cluster 47 Tucanae (47 Tuc) shows a rare increase in its velocity dispersion profile at large radii, indicative of energetic, yet bound, stars at large radii dominating the velocity dispersion and, potentially, of ongoing evaporation. Escaping stars will form tidal tails, as seen with several Galactic globular clusters, however, the tidal tails of 47 Tuc are yet to be uncovered. We model these tails of 47 Tuc using the most accurate input data available, with the specific aim of determining their locations, as well as the densities of the epicyclic overdensities within the tails. The overdensities from our models show an increase of 3-4% above the Galactic background and, therefore, should be easily detectable using matched filtering techniques. We find that the most influential parameter with regard to both the locations and densities of the epicyclic overdensities is the Heliocentric distance to the cluster. Hence, uncovering these tidal features observationally will contribute greatly to the ongoing problem of determining the distance to 47 Tuc, tightly constraining the distance of the cluster independent of other methods. Using our streakline method for determining the locations of the tidal tails and their overdensities, we show how, in principle, the shape and extent of the tidal tails of any Galactic globular cluster can be determined without resorting to computationally expensive N-body simulations.Comment: Original paper has 10 pages, 10 figures and 2 tables. Please note that this now includes an erratum. Erratum has 6 pages, 8 figures and 2 tables. Ignore the exclamation marks in Section 2 of the erratum, these are an artifact of the LaTeX class file used to produce the manuscrip

Stratigraphy and biostratigraphy of the Mississippian subsystem (carboniferous system) in its type region, the Mississippi River Valley of Illinois, Missouri and Iowa

System requirements: Adobe reader.Title from title screen.Includes bibliographical references."International Union of Geological Sciences Subcommission on Carboniferous Stratigraphy Guidebook for Field Conference, St. Louis, Missouri, September 8-13, 2001"--Title screen

The distribution of [α\alpha/Fe] in the Milky Way disc

Using a sample of red giant stars from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Data Release 16, we infer the conditional distribution $p([\alpha/\text{Fe}]\,|\,[\text{Fe/H}])$ in the Milky Way disk for the $\alpha$-elements Mg, O, Si, S, and Ca. In each bin of [Fe/H] and Galactocentric radius $R$, we model $p([\alpha/\text{Fe}])$ as a sum of two Gaussians, representing "low-$\alpha$" and "high-$\alpha$" populations with scale heights $z_1=0.45\,\text{kpc}$ and $z_2=0.95\,\text{kpc}$, respectively. By accounting for age-dependent and $z$-dependent selection effects in APOGEE, we infer the [$\alpha$/Fe] distributions that would be found for a fair sample of long-lived stars covering all $z$. Near the Solar circle, this distribution is bimodal at sub-solar [Fe/H], with the low-$\alpha$ and high-$\alpha$ peaks clearly separated by a minimum at intermediate [$\alpha$/Fe]. In agreement with previous results, we find that the high-$\alpha$ population is more prominent at smaller $R$, lower [Fe/H], and larger $|z|$, and that the sequence separation is smaller for Si and Ca than for Mg, O, and S. We find significant intrinsic scatter in [$\alpha$/Fe] at fixed [Fe/H] for both the low-$\alpha$ and high-$\alpha$ populations, typically $\sim 0.04$-dex. The means, dispersions, and relative amplitudes of this two-Gaussian description, and the dependence of these parameters on $R$, [Fe/H], and $\alpha$-element, provide a quantitative target for chemical evolution models and a test for hydrodynamic simulations of disk galaxy formation. We argue that explaining the observed bimodality will probably require one or more sharp transitions in the disk's gas accretion, star formation, or outflow history in addition to radial mixing of stellar populations.Comment: Accepted for publication in MNRA

Forests, fire and vegetation change impacts on Murray-Darling basin water resources

The Murray-Darling River system is perhaps Australia’s most important, with significant social, cultural and environmental values including 16 Ramsar listed wetlands. The MDB is home to 2.6 million people and produces about $24 billion worth in agricultural production each year (about one-third of total value for Australia). Hydrologic issues, typified by water availability and quality, have existed for many years, peaking during the Millennium drought from 1997 to 2010. Competing interests (i.e. irrigation, tourism, environmental heath), and the declining flows and water quality during droughts, led governments and water management agencies to consider the risks to water resources in the system in the early-mid 2000s. This paper reviews changes to risks associated with forest dynamics, as identified by - afforestation and bushfire–and considers new issues that have emerged since that analysis. It was found that the potential impacts of bushfire on stream flows were over-estimated in past studies, and that a planned significant afforestation expansion into agricultural and grazing land that was projected to reduce stream flows did not occur. While these two risks now do not seem likely to have significant future impacts on flows, or consequent effects on downstream users, the interaction of elevated CO2 and increasing temperatures on vegetation functioning and subsequent hydrologic consequences at catchment scale require further research and analysis. Reduced rainfall and increased temperatures under future climate change are likely to have an impact on inputs and flows. Uncertainties in how these changes, and feedbacks between climate, drought, more frequent fire and vegetation responses, impact on system hydrology also require further investigation

Evaluation of Syracuse Healthy Start’s Program for Abnormal Flora Management to Reduce Preterm Birth Among Pregnant Women

Randomized trials of bacterial vaginosis (BV) treatment among pregnant women to reduce preterm birth have had mixed results. Among non-pregnant women, BV recurs frequently after treatment. Randomized trials of early BV treatment for pregnant women in which recurrence was retreated have shown promise in reducing preterm birth. Syracuse’s Healthy Start (SHS) program began in 1997; in 1998 prenatal care providers for pregnant women living in high infant mortality zip codes were encouraged to screen for abnormal vaginal flora at the first prenatal visit. Vaginal swabs were sent to a referral hospital laboratory for Gram staining and interpretation. SHS encouraged providers to treat and rescreen women with bacterial vaginosis or abnormal flora (BV). We abstracted prenatal and hospital charts of live births between January 2000 and March 2002 for maternal conditions and treatments. We merged abstracted data with local electronic data. We evaluated the effect of BV screening before 22 weeks gestation, treatment, and rescreening using a retrospective cohort study design. Among 838 women first screened before 22 weeks, 346 (41%) had normal flora and 492 (59%) women had BV at a mean of 13 weeks gestation; 202 (24%) did not have treatment documented and 290 (35%) received treatment at a mean of 15 weeks gestation; 267 (92%) of those treated were rescreened. Among pregnant women with early BV, 42 (21%) untreated women and 28 (10%) treated women delivered preterm (Odds Ratio [OR] 0.4, 95% confidence interval [CI] 0.2–0.7)). After adjustment for age, race, prior preterm birth and other possible confounders, treatment remained associated with a reduced risk of preterm birth compared to no treatment (aOR = 0.5, 95% CI 0.3–0.9); the aOR for women with normal flora was not significantly different. Conclusion: Screening, treatment, and rescreening for BV/abnormal flora between the first prenatal visit and 22 weeks gestation showed promise in reducing preterm births and deserves further study

Are Milky-Way-like galaxies like the Milky Way? A view from SDSS-IV/MaNGA

In this paper, we place the Milky Way (MW) in the context of similar-looking galaxies in terms of their star-formation and chemical evolution histories. We select a sample of 138 Milky-Way analogues (MWAs) from the SDSS-IV/MaNGA survey based on their masses, Hubble types, and bulge-to-total ratios. To compare their chemical properties to the detailed spatially-resolved information available for the MW, we use a semi-analytic spectral fitting approach, which fits a self-consistent chemical-evolution and star-formation model directly to the MaNGA spectra. We model the galaxies' inner and outer regions assuming that some of the material lost in stellar winds falls inwards. We also incorporate chemical enrichment from type II and Ia supernovae to follow the alpha-element abundance at different metallicities and locations. We find some MWAs where the stellar properties closely reproduce the distribution of age, metallicity, and alpha enhancement at both small and large radii in the MW. In these systems, the match is driven by the longer timescale for star formation in the outer parts, and the inflow of enriched material to the central parts. However, other MWAs have very different histories. These divide into two categories: self-similar galaxies where the inner and outer parts evolve identically; and centrally-quenched galaxies where there is very little evidence of late-time central star formation driven by material accreted from the outer regions. We find that, although selected to be comparable, there are subtle morphological differences between galaxies in these different classes, and that the centrally-quenched galaxies formed their stars systematically earlier.Comment: 16 pages, 9 figures, MNRAS accepted versio