Roche tomography of cataclysmic variables - V. A high-latitude star-spot on RU Pegasi

We present Roche tomograms of the secondary star in the dwarf nova system RU Pegasi derived from blue and red arm ISIS data taken on the 4.2-m William Herschel Telescope. We have applied the entropy landscape technique to determine the system parameters and obtained component masses of M1 = 1.06 Msun, M2 = 0.96 Msun, an orbital inclination angle of i = 43 degrees, and an optimal systemic velocity of gamma = 7 km/s. These are in good agreement with previously published values. Our Roche tomograms of the secondary star show prominent irradiation of the inner Lagrangian point due to illumination by the disc and/or bright spot, which may have been enhanced as RU Peg was in outburst at the time of our observations.We find that this irradiation pattern is axi-symmetric and confined to regions of the star which have a direct view of the accretion regions. This is in contrast to previous attempts to map RU Peg which suggested that the irradiation pattern was non-symmetric and extended beyond the terminator. We also detect additional inhomogeneities in the surface distribution of stellar atomic absorption that we ascribe to the presence of a large star-spot. This spot is centred at a latitude of about 82 degrees and covers approximately 4 per cent of the total surface area of the secondary. In keeping with the high latitude spots mapped on the cataclysmic variables AE Aqr and BV Cen, the spot on RU Peg also appears slightly shifted towards the trailing hemisphere of the star. Finally, we speculate that early mapping attempts which indicated non-symmetric irradiation patterns which extended beyond the terminator of CV donors could possibly be explained by a superposition of symmetric heating and a large spot.Comment: 14 pages, 10 figures, 3 tables Accepted for publication in Monthly Notices of the Royal Astronomical Societ

Modeling Effectiveness of Low Impact Development on Runoff Volume in the Tan Brook Watershed

The Tan Brook is a heavily channelized stream that runs through an urbanized watershed in Amherst, MA. It poses a stormwater management problem for the University of Massachusetts Amherst due to flooding of soccer fields and erosion of a drainage ditch. The purpose of this study was to estimate reductions in runoff volume to the Tan Brook based on the hypothetical implementation of permeable pavements in various combinations of parking lots, driveways, roadways, and sidewalks, which cover 26% of the watershed area. A spreadsheet model-based approach utilized the Watershed Treatment Model to estimate runoff volume. The percent imperviousness of various land uses was altered to model permeable pavements. Total replacement of parking lots, roadways, sidewalks, and driveways were found to reduce runoff by 18%, 15%, 12%, and 3%, respectively. Recommendations were made to begin replacing parking lots on the UMass Amherst campus and Town of Amherst property

Effects of Elevated H\u3csup\u3e+\u3c/sup\u3e And P\u3csub\u3ei\u3c/sub\u3e on The Contractile Mechanics of Skeletal Muscle Fibres From Young and Old Men: Implications for Muscle Fatigue in Humans

The present study aimed to identify the mechanisms responsible for the loss in muscle power and increased fatigability with ageing by integrating measures of whole‐muscle function with single fibre contractile mechanics. After adjusting for the 22% smaller muscle mass in old (73–89 years, n = 6) compared to young men (20–29 years, n = 6), isometric torque and power output of the knee extensors were, respectively, 38% and 53% lower with age. Fatigability was ∼2.7‐fold greater with age and strongly associated with reductions in the electrically‐evoked contractile properties. To test whether cross‐bridge mechanisms could explain age‐related decrements in knee extensor function, we exposed myofibres (n = 254) from the vastus lateralis to conditions mimicking quiescent muscle and fatiguing levels of acidosis (H+) (pH 6.2) and inorganic phosphate (Pi) (30 mm). The fatigue‐mimicking condition caused marked reductions in force, shortening velocity and power and inhibited the low‐ to high‐force state of the cross‐bridge cycle, confirming findings from non‐human studies that these ions act synergistically to impair cross‐bridge function. Other than severe age‐related atrophy of fast fibres (−55%), contractile function and the depressive effects of the fatigue‐mimicking condition did not differ in fibres from young and old men. The selective loss of fast myosin heavy chain II muscle was strongly associated with the age‐related decrease in isometric torque (r = 0.785) and power (r = 0.861). These data suggest that the age‐related loss in muscle strength and power are primarily determined by the atrophy of fast fibres, but the age‐related increased fatigability cannot be explained by an increased sensitivity of the cross‐bridge to H+ and Pi

Expanding the CareerAdvance® Program

This report, prepared for the Health Professionals Opportunity Program, Administration for Children and Families in the U.S. Department of Health and Human Services, and the George Kaiser Family Foundation, provides the background, rationale, and overview of the first year of implementation of the CareerAdvance® program. The program aims to improve family economic security by providing low-income parents of children in Tulsa's Head Start and Early Head Start programs with workforce development services and training in high-growthpotential sectors such as healthcare and nursing, in addition to adult education programs, peer support, and performance incentives. After the first year of implementation, early signs indicate participants showing high rates of completion.Administration for Children and Families, US Dept of Health and Human Services (HHS, and the George Kaiser Family FoundationRay Marshall Center for the Study of Human Resource

Investing in Children and Parents Fostering Dual-Generation Strategies in the United States

In partnership with the Foundation for Child Development, the Ray Marshall Center is implementing a Dual-Generation Strategy Initiative. This project seeks to create and promote the field of “dual-generation” strategies, those in which children simultaneously participate in high-quality early and primary education (PreK-3rd) while their parents participate in leading-edge workforce development and education programs ultimately leading to long-term learning and economic success for low-skilled, low-income families in the United States. The goals of the project are to improve the understanding of dual-generation strategies among policymakers, researchers, and funders, as well as foster the implementation of dual-generation strategies at the federal and state levels.Foundation for Child DevelopmentRay Marshall Center for the Study of Human Resource

Recommendations for Future Efforts in RANS Modeling and Simulation

The roadmap laid out in the CFD Vision 2030 document suggests that a decision to move away from RANS research needs to be made in the current timeframe (around 2020). This paper outlines industry requirements for improved predictions of turbulent flows and the cost-barrier that is often associated with reliance on scale resolving methods. Capabilities of RANS model accuracy for simple and complex flow flow fields are assessed, and modeling practices that degrade predictive accuracy are identified. Suggested research topics are identified that have the potential to improve the applicability and accuracy of RANS models. We conclude that it is important that some part of a balanced turbulence modeling research portfolio should include RANS efforts

Dirubidium digallium oxide bis­(ortho­borate)

The title compound, Rb2Ga2O(BO3)2, is part of the homologous series A 2Ga2O(BO3)2 (A = Na, K, Rb and Cs). The structure contains pairs of gallium-centered tetra­hedra connected through a shared oxygen vertex. Orthoborate triangles connect the basal vertices of the tetra­hedra, forming a three-dimensional network with voids occupied by rubidium ions

Chemical Abundances For Evolved Stars In M5: Lithium Through Thorium

We present analysis of high-resolution spectra of a sample of stars in the globular cluster M5 (NGC 5904). The sample includes stars from the red giant branch (RGB; seven stars), the red horizontal branch (two stars), and the asymptotic giant branch (AGB; eight stars), with effective temperatures ranging from 4000 K to 6100 K. Spectra were obtained with the HIRES spectrometer on the Keck I telescope, with a wavelength coverage from 3700 angstrom to 7950 angstrom for the HB and AGB sample, and 5300 angstrom to 7600 angstrom for the majority of the RGB sample. We find offsets of some abundance ratios between the AGB and the RGB branches. However, these discrepancies appear to be due to analysis effects, and indicate that caution must be exerted when directly comparing abundance ratios between different evolutionary branches. We find the expected signatures of pollution from material enriched in the products of the hot hydrogen burning cycles such as the CNO, Ne-Na, and Mg-Al cycles, but no significant differences within these signatures among the three stellar evolutionary branches especially when considering the analysis offsets. We are also able to measure an assortment of neutron-capture element abundances, from Sr to Th, in the cluster. We find that the neutron-capture signature for all stars is the same, and shows a predominately r-process origin. However, we also see evidence of a small but consistent extra s-process signature that is not tied to the light-element variations, pointing to a pre-enrichment of this material in the protocluster gas.National Science Foundation AST-0802292NSF AST-0406988, AST-0607770, AST-0607482DFGW. M. Keck FoundationAstronom