843 research outputs found

    The Nature and Improvement of Listening Skills

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    The Nature and Improvement of Listening Skills

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    Powder Mountain Bike Resort Master Plan

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    In the last decade ski resorts worldwide have developed mountain bike specific recreational facilities in an effort to increase summer revenues. Their success has been mixed, with some becoming quite profitable, but others closing summer operations after only a few low revenue years. With minimal information regarding bike park design currently available, the planning and design of these facilities remains largely a grassroots effort. This thesis project develops a methodology that approaches the creation of mountain bike resorts on ski mountain terrain based on landscape architectural best practices, sustainable trail construction techniques, and site-specific requirements. For this project, the terrain of Powder Mountain, a privately owned ski resort above Eden, UT, was selected due to the management’s interest in the study’s relevance to expanding recreational summer offerings, and the proximity to Utah State University. This research analyzes the Powder Mountain landscape and infrastructure to develop a Master plan, outlining trail corridors, feature placement, and terrain suitability for future trail development. The basis for these design decisions were analyses from site visits, case studies, and GIS analyses. In addition, a worldwide survey of mountain bike park user experiences was conducted to further understanding of the elements of an ideal mountain bike resort. Throughout the process, these findings were augmented by consultation with professional mountain bike park designers and refined through an iterative design process to create a Master plan based on landscape architectural best practices that will guide the development of summer mountain bike recreation facilities on Powder Mountain

    Cosmological lensing ratios with DES Y1, SPT, and Planck

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    Correlations between tracers of the matter density field and gravitational lensing are sensitive to the evolution of the matter power spectrum and the expansion rate across cosmic time. Appropriately defined ratios of such correlation functions, on the other hand, depend only on the angular diameter distances to the tracer objects and to the gravitational lensing source planes. Because of their simple cosmological dependence, such ratios can exploit available signal-to-noise ratio down to small angular scales, even where directly modelling the correlation functions is difficult. We present a measurement of lensing ratios using galaxy position and lensing data from the Dark Energy Survey, and CMB lensing data from the South Pole Telescope and Planck, obtaining the highest precision lensing ratio measurements to date. Relative to the concordance ΛCDM model, we find a best-fitting lensing ratio amplitude of A = 1.1 ± 0.1. We use the ratio measurements to generate cosmological constraints, focusing on the curvature parameter. We demonstrate that photometrically selected galaxies can be used to measure lensing ratios, and argue that future lensing ratio measurements with data from a combination of LSST and Stage-4 CMB experiments can be used to place interesting cosmological constraints, even after considering the systematic uncertainties associated with photometric redshift and galaxy shear estimation

    Dirofilaria Scapiceps from the Rabbit (Sylvilagus Floridanus Mearnsi) in Ohio (Nematoda: Dipetalonematidae)

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    Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbus 1

    Measurements of E-Mode Polarization and Temperature-E-Mode Correlation in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data

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    We present measurements of E-mode polarization and temperature-E-mode correlation in the cosmic microwave background using data from the first season of observations with SPTpol, the polarization-sensitive receiver currently installed on the South Pole Telescope (SPT). The observations used in this work cover 100 deg^2 of sky with arcminute resolution at 150 GHz. We report the E-mode angular auto-power spectrum (EE) and the temperature-E-mode angular cross-power spectrum (TE) over the multipole range 500 < ℓ ≤ 5000. These power spectra improve on previous measurements in the high-ℓ (small-scale) regime. We fit the combination of the SPTpol power spectra, data from Planck, and previous SPT measurements with a six-parameter ΛCDM cosmological model. We find that the best-fit parameters are consistent with previous results. The improvement in high-ℓ sensitivity over previous measurements leads to a significant improvement in the limit on polarized point-source power: after masking sources brighter than 50 mJy in unpolarized flux at 150 GHz, we find a 95% confidence upper limit on unclustered point-source power in the EE spectrum of D_ℓ = ℓ(ℓ + 1) C_ℓ/2π < 0.40 µK^2 at ℓ = 3000, indicating that future EE measurements will not be limited by power from unclustered point sources in the multipole range ℓ < 3600, and possibly much higher in ℓ

    Measurements of the Temperature and E-mode Polarization of the CMB from 500 Square Degrees of SPTpol Data

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    We present measurements of the E-mode polarization angular auto-power spectrum (EE) and temperature–E-mode cross-power spectrum (TE) of the cosmic microwave background (CMB) using 150 GHz data from three seasons of SPTpol observations. We report the power spectra over the spherical harmonic multipole range 50 1050 and ℓ > 1475, respectively. The observations cover 500 deg^2, a fivefold increase in area compared to previous SPTpol analyses, which increases our sensitivity to the photon diffusion damping tail of the CMB power spectra enabling tighter constraints on ΛCDM model extensions. After masking all sources with unpolarized flux > 50 mJy, we place a 95% confidence upper limit on residual polarized point-source power of D_ℓ = ℓ(ℓ +1 )C_ℓ/2 π 1000 results in a preference for a higher value of the expansion rate (H_0 = 71.3 ± 2.1 km s^-1 Mpc^-1) and a lower value for present-day density fluctuations (σg_8 = 0.77 ± 0.02)

    A measurement of CMB cluster lensing with SPT and DES year 1 data

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    Clusters of galaxies gravitationally lens the cosmic microwave background (CMB) radiation, resulting in a distinct imprint in the CMB on arcminute scales. Measurement of this effect offers a promising way to constrain the masses of galaxy clusters, particularly those at high redshift. We use CMB maps from the South Pole Telescope Sunyaev–Zel'dovich (SZ) survey to measure the CMB lensing signal around galaxy clusters identified in optical imaging from first year observations of the Dark Energy Survey. The cluster catalogue used in this analysis contains 3697 members with mean redshift of z = 0.45. We detect lensing of the CMB by the galaxy clusters at 8.1σ significance. Using the measured lensing signal, we constrain the amplitude of the relation between cluster mass and optical richness to roughly 17 percent precision, finding good agreement with recent constraints obtained with galaxy lensing. The error budget is dominated by statistical noise but includes significant contributions from systematic biases due to the thermal SZ effect and cluster miscentring

    A Measurement of Gravitational Lensing of the Cosmic Microwave Background by Galaxy Clusters Using Data from the South Pole Telescope

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    Clusters of galaxies are expected to gravitationally lens the cosmic microwave background (CMB) and thereby generate a distinct signal in the CMB on arcminute scales. Measurements of this effect can be used to constrain the masses of galaxy clusters with CMB data alone. Here we present a measurement of lensing of the CMB by galaxy clusters using data from the South Pole Telescope (SPT). We develop a maximum likelihood approach to extract the CMB cluster lensing signal and validate the method on mock data. We quantify the effects on our analysis of several potential sources of systematic error and find that they generally act to reduce the best-fit cluster mass. It is estimated that this bias to lower cluster mass is roughly 0.85σ in units of the statistical error bar, although this estimate should be viewed as an upper limit. We apply our maximum likelihood technique to 513 clusters selected via their Sunyaev–Zeldovich (SZ) signatures in SPT data, and rule out the null hypothesis of no lensing at 3.1σ. The lensing-derived mass estimate for the full cluster sample is consistent with that inferred from the SZ flux: M_(200,lens)=0.83_(-0.37)^(+0.38)M_(200,SZ) (68% C.L., statistical error only)

    Cosmological lensing ratios with DES Y1, SPT, and Planck

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    Correlations between tracers of the matter density field and gravitational lensing are sensitive to the evolution of the matter power spectrum and the expansion rate across cosmic time. Appropriately defined ratios of such correlation functions, on the other hand, depend only on the angular diameter distances to the tracer objects and to the gravitational lensing source planes. Because of their simple cosmological dependence, such ratios can exploit available signal-to-noise ratio down to small angular scales, even where directly modelling the correlation functions is difficult. We present a measurement of lensing ratios using galaxy position and lensing data from the Dark Energy Survey, and CMB lensing data from the South Pole Telescope and Planck, obtaining the highest precision lensing ratio measurements to date. Relative to the concordance ΛCDM model, we find a best-fitting lensing ratio amplitude of A = 1.1 ± 0.1. We use the ratio measurements to generate cosmological constraints, focusing on the curvature parameter. We demonstrate that photometrically selected galaxies can be used to measure lensing ratios, and argue that future lensing ratio measurements with data from a combination of LSST and Stage-4 CMB experiments can be used to place interesting cosmological constraints, even after considering the systematic uncertainties associated with photometric redshift and galaxy shear estimation
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