16,484 research outputs found

    Milky Way Kinematics: Measurements at the Subcentral Point of the Fourth Quadrant

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    We use atomic hydrogen (HI) data from the Southern Galactic Plane Survey to study the kinematics of the fourth quadrant of the Milky Way. By measuring the terminal velocity as a function of longitude throughout the fourth Galactic quadrant we have derived the most densely sampled rotation curve available for the Milky Way between 3 < R < 8 kpc. We determine a new joint rotation curve fit for the first and fourth quadrants, which can be used for kinematic distances interior to the Solar circle. From our data we place new limits on the peak to peak variation of streaming motions in the fourth quadrant to be ~10 km/s. We show that the shape of the average HI profile beyond the terminal velocity is consistent with gas of three velocity dispersions, a cold component with Δv=6.3\Delta v=6.3 km/s, a warmer component with Δv=12.3\Delta v=12.3 km/s and a fast component with Δv=25.9\Delta v=25.9 km/s. Examining the widths with Galactic radius we find that the narrowest two components show little variation with radius and their small scale fluctuations track each other very well, suggesting that they share the same cloud-to-cloud motions. The width of the widest component is constant until R<4 kpc, where it increases sharply.Comment: 36 pages, 10 figures, accepted to ApJ. Full electronic version of table 1 available at ftp://ftp.atnf.csiro.au/pub/people/nmcclure/papers/velocity_tab1.te

    A Complete Atlas of HI Absorption toward HII Regions in the Southern Galactic Plane Survey (SGPS1)

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    We present a complete catalog of H I emission and absorption spectrum pairs, toward H II regions, detectable within the boundaries of the Southern Galactic Plane Survey (SGPS I), a total of 252 regions. The catalog is presented in graphical, numerical and summary formats. We demonstrate an application of this new dataset through an investigation of the locus of the Near 3kpc Arm.Comment: Accepted for publication by ApJS Feb 6, 2014. Data files and Figure Set (252 images) to appear in the on-line version of the journa

    How do impulsivity traits influence problem gambling through gambling motives? The role of perceived gambling risk/benefits.

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    Although substantial research suggests that motivations have been found to mediate the relationships between impulsivity traits and various forms of substance use, no studies have examined how gambling motives may mediate the relationships between impulsivity traits and problem gambling. The primary purpose of this study was to test an integrative model linking impulsivity traits and gambling problems, evaluating the mediating effects of gambling motives. Participants were 594 students (73% male; mean age =19.92; SD=2.91) enrolled in public high schools or universities. Young people who tend to act rashly in response to extremely positive moods, showed higher enhancement and coping motives, which in turn were positively related to gambling problems. Individuals with higher levels of sensation seeking were more likely to have higher levels of enhancement motives, which in turn were also positively related to gambling problems. The model was examined in several groups, separately for the level of perceived gambling risk/benefits (lower perceived gambling risk, higher perceived gambling risk, lower perceived gambling benefits, and higher perceived gambling benefits). There were significant differences between these groups for this division. These findings suggest that prevention and/or treatment strategies might want to consider the model’s variables, including impulsivity traits and gambling motives, in accordance with individual levels of perceived gambling risk/benefits
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