6,972 research outputs found

    Velocity-resolved observations of water in Comet Halley

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    High resolution (lambda/delta lambda approx. = 3 x 10 to the 5th power) near-infrared observations of H2O emission from Comet Halley were acquired at the time of maximum post-perihelion geocentric Doppler shift. The observed widths and absolute positions of the H2O line profiles reveal characteristics of the molecular velocity field in the coma. These results support H2O outflow from a Sun-lit hemisphere or the entire nucleus, but not from a single, narrow jet emanating from the nucleus. The measured pre- and post-perihelion outflow velocities were 0.9 + or - 0.2 and 1.4 + or - 0.2 km/s, respectively. Temporal variations in the kinematic properties of the outflow were inferred from changes in the spectral line shapes. These results are consistent with the release of H2O into the coma from multiple jets

    Examining Processes of Change for Acceptance and Commitment Therapy and Cognitive Behavioral Therapy Self-Help Books With Depressed College Students

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    Given the prevalence of depression, it is worthwhile to consider a variety of treatment approaches to reach as many sufferers as possible, including highly accessible formats such as self-help books. Books based in acceptance and commitment therapy (ACT) and cognitive behavioral therapy (CBT) propose to treat depression through distinct processes of change, though the degree to which these treatments are distinguishable in this format is unclear. Furthermore, it is possible that some individuals may respond better to therapeutic processes from one approach over the other based on personal preferences. We tested the effects of ACT and CBT self-help books on processes of change in a sample of 139 depressed college students in which some participants were given a choice of treatment and others were randomized. Cognitive fusion, which improved better in the ACT group, was the only process of change that distinguished the two treatments. Additionally, early improvements in cognitive fusion were associated with less depression-related stigma at posttreatment. Lastly, randomization, instead of choosing a treatment, led to greater improvements in almost all processes of change. We discuss how these findings inform personalized care, tangible differences between ACT and CBT, and effective practices for treating depression at large scale

    FeH Absorption in the Near-Infrared Spectra of Late M and L Dwarfs

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    We present medium-resolution z-, J-, and H-band spectra of four late-type dwarfs with spectral types ranging from M8 to L7.5. In an attempt to determine the origin of numerous weak absorption features throughout their near-infrared spectra, and motivated by the recent tentative identification of the E 4\Pi- A ^4\Pi system of FeH near 1.6 microns in umbral and cool star spectra, we have compared the dwarf spectra to a laboratory FeH emission spectrum. We have identified nearly 100 FeH absorption features in the z-, J-, and H-band spectra of the dwarfs. In particular, we have identified 34 features which dominate the appearance of the H-band spectra of the dwarfs and which appear in the laboratory FeH spectrum. Finally, all of the features are either weaker or absent in the spectrum of the L7.5 dwarf which is consistent with the weakening of the known FeH bandheads in the spectra of the latest L dwarfs.Comment: accepted by Ap

    Phase and frequency entrainment in locally coupled phase oscillators with repulsive interactions

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    Recent experiments in one and two-dimensional microfluidic arrays of droplets containing Belousov -Zhabotinsky reactants show a rich variety of spatial patterns [J. Phys. Chem. Lett. 1, 1241-1246 (2010)]. The dominant coupling between these droplets is inhibitory. Motivated by this experimental system, we study repulsively coupled Kuramoto oscillators with nearest neighbor interactions, on a linear chain as well as a ring in one dimension, and on a triangular lattice in two dimensions. In one dimension, we show using linear stability analysis as well as numerical study, that the stable phase patterns depend on the geometry of the lattice. We show that a transition to the ordered state does not exist in the thermodynamic limit. In two dimensions, we show that the geometry of the lattice constrains the phase difference between two neighbouring oscillators to 120 degrees. We report the existence of domains with either clockwise or anti-clockwise helicity, leading to defects in the lattice. We study the time dependence of these domains and show that at large coupling strengths, the domains freeze due to frequency synchronization. Signatures of the above phenomena can be seen in the spatial correlation functions.Comment: 9 pages, 12 figure

    Evaluating the Effects of Guided Coaching Calls on Engagement and Outcomes for Online Acceptance and Commitment Therapy

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    Previous research indicates mixed results for guided support with interventions. The current secondary analysis evaluated the effects of phone coaching from a dismantling trial of online acceptance and commitment therapy (ACT) in a sample of 136 distressed college students randomized to one of three versions of an ACT website. Participants were randomized to receive email prompts alone (non-coaching condition) or email plus phone coaching (coaching condition). Results indicated no differences between the coaching and non-coaching conditions on program engagement, program satisfaction, mental health outcomes, and almost all psychological flexibility processes. However, participants in the coaching condition reported stronger pre- to posttreatment improvements in psychological inflexibility than the non-coaching condition. This effect was moderated by ACT component condition, with larger pre- to posttreatment effects from coaching on psychological inflexibility in the values/committed action condition and weaker improvements from coaching in the acceptance/defusion condition. Overall, results indicate online self-guided ACT interventions with email prompts are sufficient for addressing college student mental health and that phone coaching provided minimal additional benefit

    Exotic torus manifolds and equivariant smooth structures on quasitoric manifolds

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    In 2006 Masuda and Suh asked if two compact non-singular toric varieties having isomorphic cohomology rings are homeomorphic. In the first part of this paper we discuss this question for topological generalizations of toric varieties, so-called torus manifolds. For example we show that there are homotopy equivalent torus manifolds which are not homeomorphic. Moreover, we characterize those groups which appear as the fundamental groups of locally standard torus manifolds. In the second part we give a classification of quasitoric manifolds and certain six-dimensional torus manifolds up to equivariant diffeomorphism. In the third part we enumerate the number of conjugacy classes of tori in the diffeomorphism group of torus manifolds. For torus manifolds of dimension greater than six there are always infinitely many conjugacy classes. We give examples which show that this does not hold for six-dimensional torus manifolds.Comment: 21 pages, 2 figures, results about quasitoric manifolds adde
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