4,622 research outputs found

    Kings River Quality Assurance Project Final Report

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    The Kings River Watershed Partnership non-profit citizens group formed to take local control over water quality issues in the Kings River watershed in Arkansas. One of the first items the group addressed was water quality monitoring of the Kings River and Osage Creek. To this end they formed a water quality monitoring committee that was charged with the development of a water quality monitoring plan. The objectives of the plan they developed are: 1) to characterize both spatial and temporal variability in water quality parameters throughout the watershed during each year, 2) to utilize volunteers to monitor the water quality, and 3) to institute QA/QC procedures that will insure the quality of the data collected and allow its use in development of a Watershed Management plan

    On the recovery of Local Group motion from galaxy redshift surveys

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    There is a ∼150kms−1\sim 150 km s^{-1} discrepancy between the measured motion of the Local Group of galaxies (LG) with respect to the CMB and the linear theory prediction based on the gravitational force field of the large scale structure in full-sky redshift surveys. We perform a variety of tests which show that the LG motion cannot be recovered to better than 150−200kms−1150-200 km s^{-1} in amplitude and within a ≈10∘\approx10^\circ in direction. The tests rely on catalogs of mock galaxies identified in the Millennium simulation using semi-analytic galaxy formation models. We compare these results to the Ks=11.75K_s=11.75 Two-Mass Galaxy Redshift Survey, which provides the deepest, widest and most complete spatial distribution of galaxies available so far. In our analysis we use a new, concise relation for deriving the LG motion and bulk flow from the true distribution of galaxies in redshift space. Our results show that the main source of uncertainty is the small effective depth of surveys like the 2MRS that prevents a proper sampling of the large scale structure beyond ∼100h−1Mpc\sim100 h^{-1} Mpc. Deeper redshift surveys are needed to reach the "convergence scale" of ≈250h−1Mpc\approx 250 h^{-1}Mpc in a Λ\LambdaCDM universe. Deeper survey would also mitigate the impact of the "Kaiser rocket" which, in a survey like 2MRS, remains a significant source of uncertainty. Thanks to the quiet and moderate density environment of the LG, purely dynamical uncertainties of the linear predictions are subdominant at the level of ∼90kms−1\sim 90 km s^{-1}. Finally, we show that deviations from linear galaxy biasing and shot noise errors provide a minor contribution to the total error budget.Comment: 14 pages, 7 figure

    A Reanalysis of Small Scale Velocity Dispersion in the CfA1 Survey

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    The velocity dispersion of galaxies on scales of r∼1h−1r\sim1h^{-1} Mpc, σ12(r)\sigma_{12}(r), may be estimated from the anisotropy of the galaxy-galaxy correlation function in redshift space. We present a reanalysis of the CfA1 survey, correct an error in the original analysis of Davis and Peebles (1983), and find that σ12(r)\sigma_{12}(r) is extremely sensitive to the details of how corrections for infall into the Virgo cluster are applied. We conclude that a robust value of σ12\sigma_{12} cannot be obtained from this survey. We also discuss results from other redshift surveys, including the effect of removing clusters.Comment: 12 pages, uuencoded(latex file + 2 Postscript figures), uses aas macro

    An attachment theory perspective in the examination of relational processes associated with coach-athlete dyads

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    The aim of the current study was to examine actor and partner effects of (a) athletes' and coaches' attachment styles (avoidant and anxious) on the quality of the coach-athlete relationship, and (b) athletes' and coaches' quality of the coach-athlete relationship on relationship satisfaction employing the actor-partner interdependence model (Kenny, Kashy, & Cook, 2006). Coaches (N = 107) and athletes (N = 107) completed a questionnaire related to attachment styles, relationship quality, and relationship satisfaction. Structural equation model analyses revealed (a) actor effects for coaches' and athletes' avoidant attachment styles on their own perception of relationship quality and coaches' and athletes' perception of relationship quality on their own perception of relationship satisfaction, and (b) partner effects for athletes' avoidant attachment style on coaches' perceptions of relationship quality and for coaches' perceptions of relationship quality on athletes' perceptions of relationship satisfaction. The findings highlight that attachments styles can help us understand the processes involved in the formation and maintenance of quality relational bonds between coaches and athletes

    Galaxy Tracers and Velocity Bias

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    This paper examines several methods of tracing galaxies in N-body simulations and their effects on the derived galaxy statistics, especially measurements of velocity bias. Using two simulations with identical initial conditions, one following dark matter only and the other following dark matter and baryons, both collisionless and collisional methods of tracing galaxies are compared to one another and against a set of idealized criteria. None of the collisionless methods proves satisfactory, including an elaborate scheme developed here to circumvent previously known problems. The main problem is that galactic overdensities are both secularly and impulsively disrupted while orbiting in cluster potentials. With dissipation, the baryonic tracers have much higher density contrasts and much smaller cross sections, allowing them to remain distinct within the cluster potential. The question remains whether the incomplete physical model introduces systematic biases. Statistical measures determined from simulations can vary significantly based solely on the galaxy tracing method utilized. The two point correlation function differs most on sub-cluster scales with generally good agreement on larger scales. Pairwise velocity dispersions show less uniformity on all scales addressed here. All tracing methods show a velocity bias to varying degrees, but the predictions are not firm: either the tracing method is not robust or the statistical significance has not been demonstrated. Though theoretical arguments suggest that a mild velocity bias should exist, simulation results are not yet conclusive.Comment: ApJ, in press, 23 pages, plain TeX, 8 of 13 figures included, all PostScript figures (4.8 MB) available via anonymous ftp from ftp://astro.princeton.edu/summers/tracers . Also available as POPe-616 on http://astro.princeton.edu/~library/prep.htm
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