551 research outputs found

    Frequency of Marijuana Use and Anxious and Fearful Responding to Bodily Sensations: a Laboratory Test

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    The current investigation examined the relation between frequency of marijuana use (no history of use, regular low-frequency use, and regular high-frequency use) and anxious and fearful responding to a biological challenge paradigm. Ninety-six participants (mage = 22.60, SD = 9.01, 45 females) were recruited from the greater Burlington, Vermont community and matched on gender, alcohol, and tobacco use. Primary results indicated that frequency of marijuana use was not significantly related to post-challenge panic attack symptoms, interest in returning for another challenge (behavioral avoidance), or changes in anxiety focused on bodily sensations, heart rate, or respiration rate (breaths per minute). Post hoc analyses suggested that, among current users of marijuana, those who were dependent on marijuana had greater panic attack symptoms post-challenge than those who abused marijuana. Further analyses indicated that, among current marijuana users, those who used the drug for coping reasons were significantly more likely to exhibit greater avoidance post-challenge as well as greater panic attack symptoms post-challenge than those who primarily used for other motives. Additionally, greater frequency of marijuana use among current users was related to less avoidance post-challenge. Findings of the investigation are discussed in relation to clarifying which factors of marijuana use may play a role in anxious and fearful responding to bodily sensations

    Microwave Spectroscopy of Thermally Excited Quasiparticles in YBa_2Cu_3O_{6.99}

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    We present here the microwave surface impedance of a high purity crystal of YBa2Cu3O6.99YBa_2Cu_3O_{6.99} measured at 5 frequencies between 1 and 75 GHz. This data set reveals the main features of the conductivity spectrum of the thermally excited quasiparticles in the superconducting state. Below 20 K there is a regime of extremely long quasiparticle lifetimes, due to both the collapse of inelastic scattering below TcT_c and the very weak impurity scattering in the high purity BaZrO3BaZrO_3-grown crystal used in this study. Above 20 K, the scattering increases dramatically, initially at least as fast as T4T^4.Comment: 13 pages with 10 figures. submitted to Phys Rev

    Generalized Statistics and High Tc Superconductivity

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    Introducing the generalized, non-extensive statistics proposed by Tsallis[1988], into the standard s-wave pairing BCS theory of superconductivity in 2D yields a reasonable description of many of the main properties of high temperature superconductors, provided some allowance is made for non-phonon mediated interactions.Comment: 14 pages, 5 figure

    Melting and Dimensionality of the Vortex Lattice in Underdoped YBa2Cu3O6.60

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    Muon spin rotation measurements of the magnetic field distribution in the vortex state of the oxygen deficient high-Tc superconductor YBa{2}Cu{3}O{6.60} reveal a vortex-lattice melting transition at much lower temperature than that in the fully oxygenated material. The transition is best described by a model in which adjacent layers of ``pancake'' vortices decouple in the liquid phase. Evidence is also found for a pinning-induced crossover from a solid 3D to quasi-2D vortex lattice, similar to that observed in the highly anisotropic superconductor Bi{2+x}Sr{2-x}CaCu{2}O{8+y}.Comment: 8 pages, 4 figures, 5 postscript file

    Outcomes in a community sex offender treatment program: A comparison between polygraphed and matched non-polygraphed offenders. Sexual Abuse: A

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    Abstract This study compared a group of 104 adult male sex offenders who received community cognitive-behavioral treatment, correctional supervision, and periodic polygraph compliance exams with a matched group of 104 sex offenders who received the same type of treatment and supervision services but no polygraph exams. Polygraph exams focused on whether participants were following their conditions of community supervision and treatment and had avoided committing new sexual offenses. The two groups were exact pair-wise matched on three variables: (1) Static-99 risk score (Hanson & Thornton 2000, Law and Human Behavior, 24, 119-136), (2) status as a completer of prison sex offender treatment, and (3) date placed in the community. At fixed 5-year follow-up periods, the number of individuals in the polygraph group charged with committing a new non-sexual violent offense was significantly lower than in the no polygraph group (2.9% versus 11.5%). However, there were no significant between-group differences for the number of individuals charged for new sexual (5.8% versus 6.7%), any sexual or violent (8.7% versus 16.3%), or any criminal offense (39.4% versus 34.6%). The results are discussed in terms of their clinical and research implications

    Evidence for Static Magnetism in the Vortex Cores of Ortho-II YBa2_2Cu3_3O6.50_{6.50}

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    Evidence for static alternating magnetic fields in the vortex cores of underdoped YBa2_2Cu3_3O6+x_{6+x} is reported. Muon spin rotation measurements of the internal magnetic field distribution of the vortex state of YBa2_2Cu3_3O6.50_{6.50} in applied fields of H=1H = 1 T and H=4H = 4 T reveal a feature in the high-field tail of the field distribution which is not present in optimally doped YBa2_2Cu3_3O6.95_{6.95} and which fits well to a model with static magnetic fields in the vortex cores. The magnitude of the fields is estimated to be 18(2) G and decreases above T=10T = 10 K. We discuss possible origins of the additional vortex core magnetism within the context of existing theories.Comment: Submitted to PRL; corresponding author: [email protected]

    Background risk of breast cancer and the association between physical activity and mammographic density

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    This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/ by/4.0

    MRI investigation of granular interface rheology using a new cylinder shear apparatus

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    The rheology of granular materials near an interface is investigated through proton magnetic resonance imaging. A new cylinder shear apparatus has been inserted in the MRI device, which allows the control of the radial confining pressure exerted by the outer wall on the grains and the measurement of the torque on the inner shearing cylinder. A multi-layer velocimetry sequence has been developed for the simultaneous measurement of velocity profiles in different sample zones, while the measurement of the solid fraction profile is based on static imaging of the sample. This study describes the influence of the roughness of the shearing interface and of the transverse confining walls on the granular interface rheology
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