2,662 research outputs found

    Wading the Creek in Eastern Kentucky

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    A thesis presented to the faculty of the Caudill College of Humanities at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Arts in English by Chris Turner on July 28, 1997

    The effect of temperature-dependent solubility on the onset of thermosolutal convection in a horizontal porous layer

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    We consider the onset of thermosolutal (double-diffusive) convection of a binary fluid in a horizontal porous layer subject to fixed temperatures and chemical equilibrium on the bounding surfaces, in the case when the solubility of the dissolved component depends on temperature. We use a linear stability analysis to investigate how the dissolution or precipitation of this component affects the onset of convection and the selection of an unstable wavenumber; we extend this analysis using a Galerkin method to predict the structure of the initial bifurcation and compare our analytical results with numerical integration of the full nonlinear equations. We find that the reactive term may be stabilizing or destabilizing, with subtle effects particularly when the thermal gradient is destabilizing but the solutal gradient is stabilizing. The preferred spatial wavelength of convective cells at onset may also be substantially increased or reduced, and strongly reactive systems tend to prefer direct to subcritical bifurcation. These results have implications for geothermal-reservoir management and ore prospecting

    E-learning at University of the Arts London

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    This report is a systematic exploration of staff relationships with e-learning. It presents a renewed evidence base from which e-learning provision and related support can be planned particularly in a rapidly changing HE terrain and an institutional context where e-learning and academic structures are emerging from large change programmes. The research is based on 25 interviews with programme directors (PD) evenly distributed across the 4 colleges, with representatives from all discipline groups, and levels of study. The interviewees provided rich insights into attitudes to, practices in and aspirations for e-learning, but in some instances, were also limited by the newness of the PD role. While some PDs had an intimate understanding of their programme areas, others, understandably, given the newness of posts, were in the process of familiarising themselves with the work of their teams

    An investigation of Australian and New Zealand hotel ownership

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    The results of a study seeking to advance a typology of hotel owners as well as examining the composition of hotel owners in Australia and New Zealand are reported. Interview observations resulted in the six hotel ownership categories, discernible from prior commentaries, being broadened to nine hotel owner types. Considerable insights with respect to differentials in the investment time horizon and capital expenditure strategy applied by different owner types were gleaned from the interview data. From a questionnaire survey phase it was found that high net worth private investors and hotel management companies each own approximately a quarter of large 3-5 star Australian and New Zealand hotels. Several distinct hotel operational characteristics are also apparent across the hotel owner types. These include the observation that developer, high net worth investor and strata-title owned hotels tend to be smaller in terms of revenue generated and also these owner types tend to own less hotels. Also, general managers tend to hold their position for shorter periods in hotels owned by hotel management companies and high net worth private investors tend to own older hotels

    Biases in velocity reconstruction: investigating the effects on growth rate and expansion measurements in the local universe

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    The local galaxy peculiar velocity field can be reconstructed from the surrounding distribution of large-scale structure and plays an important role in calibrating cosmic growth and expansion measurements. In this paper, we investigate the effect of the stochasticity of these velocity reconstructions on the statistical and systematic errors in cosmological inferences. By introducing a simple statistical model between the measured and theoretical velocities, whose terms we calibrate from linear theory, we derive the bias in the model velocity. We then use lognormal realisations to explore the potential impact of this bias when using a cosmic flow model to measure the growth rate of structure, and to sharpen expansion rate measurements from host galaxies for gravitational wave standard sirens with electromagnetic counterparts. Although our illustrative study does not contain fully realistic observational effects, we demonstrate that in some scenarios these corrections are significant and result in a measurable improvement in determinations of the Hubble constant compared to standard forecasts.Comment: 10 pages, 10 figures, 1 table, 1 appendix. Submitted to MNRAS. Comments welcom

    On the correlations of galaxy peculiar velocities and their covariance

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    Measurements of the peculiar velocities of large samples of galaxies enable new tests of the standard cosmological model, including determination of the growth rate of cosmic structure that encodes gravitational physics. With the size of such samples now approaching hundreds of thousands of galaxies, complex statistical analysis techniques and models are required to extract cosmological information. In this paper we summarise how correlation functions between galaxy velocities, and with the surrounding large-scale structure, may be utilised to test cosmological models. We present new determinations of the analytical covariance between such correlation functions, which may be useful for cosmological likelihood analyses. The statistical model we use to determine these covariances includes the sample selection functions, observational noise, curved-sky effects and redshift-space distortions. By comparing these covariance determinations with corresponding estimates from large suites of cosmological simulations, we demonstrate that these analytical models recover the key features of the covariance between different statistics and separations, and produce similar measurements of the growth rate of structure.Comment: 20 pages, 9 figures, version accepted for publication by MNRA
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