148 research outputs found

    Parental Abuse, Risky Behavior and Psychopathic Traits in Adolescents and Early Adults

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    This study examines the associations between parental abuse, risky behavior, and affective psychopathic traits. Ninety-one (49% males) rural adolescents and young adults (between the ages of fourteen and twenty-five) participated in an investigation of gene and environment interactions. The sample consisted of high school and undergraduate college students. These participants provided self-reports of parental abuse, risky behaviors, and psychopathic affective traits. Results suggested that psychopathic traits, especially a lack of remorse and parental abuse, independently account for some risky behavior.https://digitalcommons.mtech.edu/urp_aug_2013/1001/thumbnail.jp

    Solar wind and seasonal influence on ionospheric currents from Swarm and CHAMP measurements

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    We present a new climatological model of the ionospheric current system, determined from magnetic measurements taken by the Challenging Minisatellite Payload (CHAMP) and Swarm satellites. The model describes the horizontal currents in the ionosphere, below the satellites, and the field-aligned (Birkeland) currents that connect the ionosphere with the magnetosphere. The model provides ionospheric current values at any location as continuous functions of solar wind speed, interplanetary magnetic field, dipole tilt angle, and the F10.7 index of solar flux. Geometric distortions due to variations in the Earth’s main magnetic field are taken into account, thus allowing for precise comparisons between the two hemispheres. The model is the first of its kind to describe the full 3-D electric currents and not only the field-aligned or the equivalent horizontal current. We use this capability to demonstrate a key difference between seasons: During winter, the total horizontal current is almost entirely confined to the auroral oval, for all interplanetary magnetic field orientations, where it connects upward and downward Birkeland currents. During more sunlit conditions, the horizontal current extends beyond the auroral oval and is a sum of currents connecting Birkeland currents and currents that circulate in the ionosphere. The westward electrojet is the only large-scale current structure that is persistent across seasons. Comparison with average convection maps suggests that it is comprised largely of Hall currents, which connect to Birkeland currents in the winter but not in summer.publishedVersio

    An analysis of magnetic reconnection events and their associated auroral enhancements

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    An analysis of simultaneous reconnection events in the near-Earth magnetotail and enhancements in the aurora is undertaken. Exploiting magnetospheric data from the Geotail, Cluster, and Double Star missions, along with auroral images from the IMAGE and Polar missions, the relationship between a reconnection signature and its auroral counterpart is explored. In this study of 59 suitable reconnection events, we find that 43 demonstrate a clear coincidence of reconnection and auroral enhancement. The magnetic local time (MLT) locations of these 43 reconnection events are generally located within ±1 h MLT of the associated auroral enhancement. A positive correlation coefficient of 0.8 between the two MLT locations is found. The enhancements are localized and short-lived (τ≤10 min) and are as likely to occur during the substorm process as in isolation of a substorm. No significant dependence of the reconnection or auroral enhancement location on the dusk-dawn components of the solar wind velocity (Vy), IMF (By) or local By or Vy, as measured by the reconnection-detecting spacecraft, is found

    How the IMF By\mathit{B}_{y} Induces a Local By\mathit{B}_{y} Component During Northward IMF Bz\mathit{B}_{z} and Characteristic Timescales

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    We use the Lyon-Fedder-Mobarry global magnetohydrodynamics model to study the effects of the interplanetary magnetic field (IMF) By\mathit{B}_{y} component on the coupling between the solar wind and magnetosphere-ionosphere system when IMF Bz\mathit{B}_{z} >>0. We describe the evolution of how a magnetospheric By\mathit{B}_{y} component is induced on closed field lines during these conditions. Starting from dayside lobe reconnection, the magnetic tension on newly reconnected field lines redistribute the open flux asymmetrically between the two hemispheres. This results in asymmetric magnetic energy density in the lobes. Shear flows are induced to restore equilibrium, and these flows are what effectively induces a local By\mathit{B}_{y} component. We show the radial dependence of the induced By\mathit{B}_{y} and compare the results to the induced By\mathit{B}_{y} during southward IMF conditions. We also show the response and reconfiguration time of the inner magnetosphere to IMF By\mathit{B}_{y} reversals during northward IMF Bz\mathit{B}_{z}. A superposed epoch analysis of magnetic field measurements from seven Geostationary Operational Environmental Satellite spacecraft at different local times both for negative-to-positive and positive-to-negative IMF By\mathit{B}_{y} reversals is presented. We find that the induced By\mathit{B}_{y} responds within 16 min of the arrival of IMF By\mathit{B}_{y} at the bow shock, and it completely reconfigures within 47 min

    Development of the Techology for Intermediate Energy Electron Cooling

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    This research was sponsored by the National Science Foundation Grant NSF PHY-931478

    Dynamic effects of restoring footpoint symmetry on closed magnetic field lines

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    Here we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from conjugate auroral imaging. This is interpreted as evidence of closed field lines having very asymmetric footpoints associated with the persistent positive y component of the interplanetary magnetic field before and during the event. At the same time, the Super Dual Auroral Radar Network observes the ionospheric nightside convection throat region in both hemispheres. The radar data indicate faster convection toward the dayside in the dusk cell in the Southern Hemisphere compared to its conjugate region. We interpret this as a signature of a process acting to restore symmetry of the displaced closed magnetic field lines resulting in flux tubes moving faster along the banana cell than the conjugate orange cell. The event is analyzed with emphasis on Birkeland currents (BC) associated with this restoring process, as recently described by Tenfjord et al. (2015). Using data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during the same conditions as the presented event, the large-scale BC pattern associated with the event is presented. It shows the expected influence of the process of restoring symmetry on BCs. We therefore suggest that these observations should be recognized as being a result of the dynamic effects of restoring footpoint symmetry on closed field lines in the nightside
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