1,244 research outputs found

    Effectiveness of a Multimodal Mindfulness Program for Student Health Care Professionals: A Randomized Controlled Trial

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    Background: The effectiveness of a multimodal mindfulness program incorporating traditional and nontraditional forms of active and nonactive meditation practices with a sample of occupational and physical therapy students was assessed in this study. Method: Thirty-six participants were randomly assigned to an intervention or control group. The 8-week mindfulness program consisted of one weekly 40-min in-person group session and four weekly 10-min online guided meditations. Pre and postintervention measures included the Perceived Stress Scale (PSS), Student Stress Management Scale (SSMS), mindfulness activity log, open-ended qualitative questionnaire, GPA, and counseling visit frequency. Results: Statistically significant differences, with large effect sizes, were found between intervention and control group PSS (Z=-4.291, pd=-1.84) and SSMS (Z=-3.330, pd=-1.27) postintervention scores. Statistically significant differences, with large effect sizes, were found between intervention group pre and postmindfulness activity ratings for each week and all weeks combined (Z=-12.599, pd=1.29). Qualitative data revealed eight themes including greater sleep quality, energy levels, self-compassion, and life-work balance. No statistically significant differences were found between intervention and control group counseling visit frequency and GPA. Conclusion: As this is preliminary data about a novel intervention with a small student sample, effectiveness of this intervention should be further explored in a replication study

    Spatio-Velocity CSF as a Function of Retinal Velocity Using Unstabilized Stimuli

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    LCD televisions have LC response times and hold-type data cycles that contribute to the appearance of blur when objects are in motion on the screen. New algorithms based on studies of the human visual system\u27s sensitivity to motion are being developed to compensate for these artifacts. This paper describes a series of experiments that incorporate eyetracking in the psychophysical determination of spatio-velocity contrast sensitivity in order to build on the 2D spatiovelocity contrast sensitivity function (CSF) model first described by Kelly and later refined by Daly. We explore whether the velocity of the eye has an additional effect on sensitivity and whether the model can be used to predict sensitivity to more complex stimuli. There were a total of five experiments performed in this research. The first four experiments utilized Gabor patterns with three different spatial and temporal frequencies and were used to investigate and/or populate the 2D spatio-velocity CSF. The fifth experiment utilized a disembodied edge and was used to validate the model. All experiments used a two interval forced choice (2IFC) method of constant stimuli guided by a QUEST routine to determine thresholds. The results showed that sensitivity to motion was determined by the retinal velocity produced by the Gabor patterns regardless of the type of motion of the eye. Based on the results of these experiments the parameters for the spatio-velocity CSF model were optimized to our experimental conditions

    Semiparametric Bayesian inference in smooth coefficient models

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    We describe procedures for Bayesian estimation and testing in cross-sectional, panel data and nonlinear smooth coefficient models. The smooth coefficient model is a generalization of the partially linear or additive model wherein coefficients on linear explanatory variables are treated as unknown functions of an observable covariate. In the approach we describe, points on the regression lines are regarded as unknown parameters and priors are placed on differences between adjacent points to introduce the potential for smoothing the curves. The algorithms we describe are quite simple to implement - for example, estimation, testing and smoothing parameter selection can be carried out analytically in the cross-sectional smooth coefficient model. We apply our methods using data from the National Longitudinal Survey of Youth (NLSY). Using the NLSY data we first explore the relationship between ability and log wages and flexibly model how returns to schooling vary with measured cognitive ability. We also examine a model of female labor supply and use this example to illustrate how the described techniques can been applied in nonlinear settings

    The Demographics and Atmospheres of Giant Planets with the ELTs

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    Gas giants are the most readily detectable exoplanets but fundamental questions about their system architectures, formation, migration, and atmospheres have been unanswerable with the current generation of ground- and space-based facilities. The dominant techniques to detect and characterize giant planets −- radial velocities, transits, direct imaging, microlensing, and astrometry −- are each isolated to a limited range of planet masses, separations, ages, and temperatures. These windows into the arrangement and physical properties of giant planets have spawned new questions about the timescale and location of their assembly; the distributions of planet mass and orbital separation at young and old ages; the composition and structure of their atmospheres; and their orbital and rotational angular momentum architectures. The ELTs will address these questions by building bridges between these islands of mass, orbital distance, and age. The angular resolution, collecting area, all-sky coverage, and novel instrumentation suite of these facilities are needed to provide a complete map of the orbits and atmospheric evolution of gas giant planets (0.3−-10 MJupM_\mathrm{Jup}) across space (0.1−-100 AU) and time (1 Myr to 10 Gyr). This white paper highlights the scientific potential of the GMT and TMT to address these outstanding questions, with a particular focus on the role of direct imaging and spectroscopy of large samples of giant planets that will soon be made available with GaiaGaia.Comment: White paper for the Astro2020 decadal surve

    High contrast imaging at the LBT: the LEECH exoplanet imaging survey

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    In Spring 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its ∼\sim130-night campaign from the Large Binocular Telescope (LBT) atop Mt Graham, Arizona. This survey benefits from the many technological achievements of the LBT, including two 8.4-meter mirrors on a single fixed mount, dual adaptive secondary mirrors for high Strehl performance, and a cold beam combiner to dramatically reduce the telescope's overall background emissivity. LEECH neatly complements other high-contrast planet imaging efforts by observing stars at L' (3.8 μ\mum), as opposed to the shorter wavelength near-infrared bands (1-2.4 μ\mum) of other surveys. This portion of the spectrum offers deep mass sensitivity, especially around nearby adolescent (∼\sim0.1-1 Gyr) stars. LEECH's contrast is competitive with other extreme adaptive optics systems, while providing an alternative survey strategy. Additionally, LEECH is characterizing known exoplanetary systems with observations from 3-5μ\mum in preparation for JWST.Comment: 12 pages, 5 figures. Proceedings of the SPIE, 9148-2

    The LEECH Exoplanet Imaging Survey: Limits on Planet Occurrence Rates Under Conservative Assumptions

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    We present the results of the largest L′L^{\prime} (3.8 μ3.8~\mum) direct imaging survey for exoplanets to date, the Large Binocular Telescope Interferometer (LBTI) Exozodi Exoplanet Common Hunt (LEECH). We observed 98 stars with spectral types from B to M. Cool planets emit a larger share of their flux in L′L^{\prime} compared to shorter wavelengths, affording LEECH an advantage in detecting low-mass, old, and cold-start giant planets. We emphasize proximity over youth in our target selection, probing physical separations smaller than other direct imaging surveys. For FGK stars, LEECH outperforms many previous studies, placing tighter constraints on the hot-start planet occurrence frequency interior to ∼20\sim20 au. For less luminous, cold-start planets, LEECH provides the best constraints on giant-planet frequency interior to ∼20\sim20 au around FGK stars. Direct imaging survey results depend sensitively on both the choice of evolutionary model (e.g., hot- or cold-start) and assumptions (explicit or implicit) about the shape of the underlying planet distribution, in particular its radial extent. Artificially low limits on the planet occurrence frequency can be derived when the shape of the planet distribution is assumed to extend to very large separations, well beyond typical protoplanetary dust-disk radii (≲50\lesssim50 au), and when hot-start models are used exclusively. We place a conservative upper limit on the planet occurrence frequency using cold-start models and planetary population distributions that do not extend beyond typical protoplanetary dust-disk radii. We find that ≲90%\lesssim90\% of FGK systems can host a 7 to 10 MJupM_{\mathrm{Jup}} planet from 5 to 50 au. This limit leaves open the possibility that planets in this range are common.Comment: 31 pages, 13 figures, accepted to A
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